diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2d4f40f3..51958910 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ and this project attempts to adhere to [Semantic Versioning](https://semver.org/
 
 ### Added
 
+- Added `diagnostics.severity` configuration option for configuring diagnostic severity levels
 - Added `pythonpath` configuration option for specifying additional Python import paths
 - Added documentation for VS Code extension
 - Added documentation for Zed extension
diff --git a/crates/djls-bench/Cargo.toml b/crates/djls-bench/Cargo.toml
index f3c59535..4ce07d22 100644
--- a/crates/djls-bench/Cargo.toml
+++ b/crates/djls-bench/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.0.0"
 edition = "2021"
 
 [dependencies]
+djls-conf = { workspace = true }
 djls-source = { workspace = true }
 djls-templates = { workspace = true }
 djls-semantic = { workspace = true }
diff --git a/crates/djls-bench/src/db.rs b/crates/djls-bench/src/db.rs
index bc00230e..7ed0d7bb 100644
--- a/crates/djls-bench/src/db.rs
+++ b/crates/djls-bench/src/db.rs
@@ -85,4 +85,8 @@ impl SemanticDb for Db {
     fn template_dirs(&self) -> Option<Vec<Utf8PathBuf>> {
         None
     }
+
+    fn diagnostics_config(&self) -> djls_conf::DiagnosticsConfig {
+        djls_conf::DiagnosticsConfig::default()
+    }
 }
diff --git a/crates/djls-conf/src/diagnostics.rs b/crates/djls-conf/src/diagnostics.rs
new file mode 100644
index 00000000..46682c09
--- /dev/null
+++ b/crates/djls-conf/src/diagnostics.rs
@@ -0,0 +1,261 @@
+use std::collections::HashMap;
+
+use serde::Deserialize;
+
+/// Diagnostic severity level for LSP diagnostics.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum DiagnosticSeverity {
+    Off,
+    Error,
+    Warning,
+    Info,
+    Hint,
+}
+
+/// Configuration for diagnostic severity levels.
+///
+/// All diagnostics are enabled by default at "error" severity.
+/// Configure severity per diagnostic code or prefix pattern.
+/// Specific codes override prefix patterns.
+///
+/// Example configuration:
+/// ```toml
+/// [tool.djls.diagnostics.severity]
+/// # Individual codes
+/// S101 = "warning"
+/// S102 = "off"
+///
+/// # Prefixes for bulk configuration
+/// "T" = "off"     # Disable all template errors
+/// T100 = "hint"   # But show parser errors as hints (specific overrides prefix)
+/// ```
+#[derive(Debug, Clone, PartialEq, Deserialize, Default)]
+pub struct DiagnosticsConfig {
+    /// Map of diagnostic codes/prefixes to severity levels.
+    /// Supports:
+    /// - Specific codes: "S100", "T100"
+    /// - Prefixes: "S" (all S-series), "T" (all T-series), "S1" (S100-S199)
+    /// - More specific patterns override less specific ones
+    #[serde(default)]
+    severity: HashMap<String, DiagnosticSeverity>,
+}
+
+impl DiagnosticsConfig {
+    /// Get the severity level for a diagnostic code.
+    ///
+    /// Resolution order (most specific wins):
+    /// 1. Exact match (e.g., "S100")
+    /// 2. Longest prefix match (e.g., "S1" over "S")
+    /// 3. Default: Error
+    #[must_use]
+    pub fn get_severity(&self, code: &str) -> DiagnosticSeverity {
+        // First, check for exact match
+        if let Some(&severity) = self.severity.get(code) {
+            return severity;
+        }
+
+        // Then, find the longest matching prefix
+        let mut best_match: Option<(&str, DiagnosticSeverity)> = None;
+
+        for (pattern, &severity) in &self.severity {
+            if code.starts_with(pattern) {
+                match best_match {
+                    None => best_match = Some((pattern, severity)),
+                    Some((existing_pattern, _)) => {
+                        // Longer patterns are more specific
+                        if pattern.len() > existing_pattern.len() {
+                            best_match = Some((pattern, severity));
+                        }
+                    }
+                }
+            }
+        }
+
+        best_match.map_or(DiagnosticSeverity::Error, |(_, severity)| severity)
+    }
+
+    /// Check if a diagnostic should be shown (severity is not Off).
+    #[must_use]
+    pub fn is_enabled(&self, code: &str) -> bool {
+        self.get_severity(code) != DiagnosticSeverity::Off
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_get_severity_default() {
+        let config = DiagnosticsConfig::default();
+        assert_eq!(config.get_severity("S100"), DiagnosticSeverity::Error);
+        assert_eq!(config.get_severity("T100"), DiagnosticSeverity::Error);
+    }
+
+    #[test]
+    fn test_get_severity_exact_match() {
+        let mut severity = HashMap::new();
+        severity.insert("S100".to_string(), DiagnosticSeverity::Warning);
+        severity.insert("S101".to_string(), DiagnosticSeverity::Off);
+
+        let config = DiagnosticsConfig { severity };
+
+        assert_eq!(config.get_severity("S100"), DiagnosticSeverity::Warning);
+        assert_eq!(config.get_severity("S101"), DiagnosticSeverity::Off);
+        assert_eq!(config.get_severity("S102"), DiagnosticSeverity::Error);
+    }
+
+    #[test]
+    fn test_get_severity_prefix_match() {
+        let mut severity = HashMap::new();
+        severity.insert("S".to_string(), DiagnosticSeverity::Warning);
+        severity.insert("T".to_string(), DiagnosticSeverity::Off);
+
+        let config = DiagnosticsConfig { severity };
+
+        assert_eq!(config.get_severity("S100"), DiagnosticSeverity::Warning);
+        assert_eq!(config.get_severity("S101"), DiagnosticSeverity::Warning);
+        assert_eq!(config.get_severity("T100"), DiagnosticSeverity::Off);
+        assert_eq!(config.get_severity("T900"), DiagnosticSeverity::Off);
+    }
+
+    #[test]
+    fn test_get_severity_longest_prefix_wins() {
+        let mut severity = HashMap::new();
+        severity.insert("S".to_string(), DiagnosticSeverity::Warning);
+        severity.insert("S1".to_string(), DiagnosticSeverity::Off);
+        severity.insert("S10".to_string(), DiagnosticSeverity::Hint);
+
+        let config = DiagnosticsConfig { severity };
+
+        // S10 is most specific for S100
+        assert_eq!(config.get_severity("S100"), DiagnosticSeverity::Hint);
+        assert_eq!(config.get_severity("S101"), DiagnosticSeverity::Hint);
+        // S1 is most specific for S110
+        assert_eq!(config.get_severity("S110"), DiagnosticSeverity::Off);
+        assert_eq!(config.get_severity("S199"), DiagnosticSeverity::Off);
+        // S is most specific for S200
+        assert_eq!(config.get_severity("S200"), DiagnosticSeverity::Warning);
+    }
+
+    #[test]
+    fn test_get_severity_exact_overrides_prefix() {
+        let mut severity = HashMap::new();
+        severity.insert("S".to_string(), DiagnosticSeverity::Warning);
+        severity.insert("S1".to_string(), DiagnosticSeverity::Off);
+        severity.insert("S100".to_string(), DiagnosticSeverity::Error);
+
+        let config = DiagnosticsConfig { severity };
+
+        // Exact match wins
+        assert_eq!(config.get_severity("S100"), DiagnosticSeverity::Error);
+        // S1 prefix for other S1xx codes
+        assert_eq!(config.get_severity("S101"), DiagnosticSeverity::Off);
+        // S prefix for S2xx codes
+        assert_eq!(config.get_severity("S200"), DiagnosticSeverity::Warning);
+    }
+
+    #[test]
+    fn test_is_enabled_default() {
+        let config = DiagnosticsConfig::default();
+        assert!(config.is_enabled("S100"));
+        assert!(config.is_enabled("T100"));
+    }
+
+    #[test]
+    fn test_is_enabled_with_off() {
+        let mut severity = HashMap::new();
+        severity.insert("S100".to_string(), DiagnosticSeverity::Off);
+
+        let config = DiagnosticsConfig { severity };
+
+        assert!(!config.is_enabled("S100"));
+        assert!(config.is_enabled("S101"));
+    }
+
+    #[test]
+    fn test_is_enabled_with_prefix_off() {
+        let mut severity = HashMap::new();
+        severity.insert("T".to_string(), DiagnosticSeverity::Off);
+
+        let config = DiagnosticsConfig { severity };
+
+        assert!(!config.is_enabled("T100"));
+        assert!(!config.is_enabled("T900"));
+        assert!(config.is_enabled("S100"));
+    }
+
+    #[test]
+    fn test_is_enabled_prefix_off_with_specific_override() {
+        let mut severity = HashMap::new();
+        severity.insert("T".to_string(), DiagnosticSeverity::Off);
+        severity.insert("T100".to_string(), DiagnosticSeverity::Hint);
+
+        let config = DiagnosticsConfig { severity };
+
+        // T100 has specific override, so it's enabled
+        assert!(config.is_enabled("T100"));
+        // Other T codes are off
+        assert!(!config.is_enabled("T900"));
+        assert!(!config.is_enabled("T901"));
+    }
+
+    #[test]
+    fn test_deserialize_diagnostics_config() {
+        let toml = r#"
+            [severity]
+            S100 = "off"
+            S101 = "warning"
+            S102 = "hint"
+            "T" = "off"
+            T100 = "info"
+        "#;
+
+        let config: DiagnosticsConfig = toml::from_str(toml).unwrap();
+        assert_eq!(config.get_severity("S100"), DiagnosticSeverity::Off);
+        assert_eq!(config.get_severity("S101"), DiagnosticSeverity::Warning);
+        assert_eq!(config.get_severity("S102"), DiagnosticSeverity::Hint);
+        // T prefix applies to T900
+        assert_eq!(config.get_severity("T900"), DiagnosticSeverity::Off);
+        // T100 has specific override
+        assert_eq!(config.get_severity("T100"), DiagnosticSeverity::Info);
+    }
+
+    #[test]
+    fn test_complex_scenario() {
+        let mut severity = HashMap::new();
+        // Disable all template errors
+        severity.insert("T".to_string(), DiagnosticSeverity::Off);
+        // But show parser errors as hints
+        severity.insert("T100".to_string(), DiagnosticSeverity::Hint);
+        // Make all semantic errors warnings
+        severity.insert("S".to_string(), DiagnosticSeverity::Warning);
+        // Except S100 which is completely off
+        severity.insert("S100".to_string(), DiagnosticSeverity::Off);
+        // And S10x (S100-S109) should be info
+        severity.insert("S10".to_string(), DiagnosticSeverity::Info);
+
+        let config = DiagnosticsConfig { severity };
+
+        // S100 is exact match - off
+        assert_eq!(config.get_severity("S100"), DiagnosticSeverity::Off);
+        assert!(!config.is_enabled("S100"));
+
+        // S101 matches S10 prefix - info
+        assert_eq!(config.get_severity("S101"), DiagnosticSeverity::Info);
+        assert!(config.is_enabled("S101"));
+
+        // S200 matches S prefix - warning
+        assert_eq!(config.get_severity("S200"), DiagnosticSeverity::Warning);
+        assert!(config.is_enabled("S200"));
+
+        // T100 has exact match - hint
+        assert_eq!(config.get_severity("T100"), DiagnosticSeverity::Hint);
+        assert!(config.is_enabled("T100"));
+
+        // T900 matches T prefix - off
+        assert_eq!(config.get_severity("T900"), DiagnosticSeverity::Off);
+        assert!(!config.is_enabled("T900"));
+    }
+}
diff --git a/crates/djls-conf/src/lib.rs b/crates/djls-conf/src/lib.rs
index 11573707..1eb41be3 100644
--- a/crates/djls-conf/src/lib.rs
+++ b/crates/djls-conf/src/lib.rs
@@ -1,3 +1,4 @@
+pub mod diagnostics;
 pub mod tagspecs;
 
 use std::fs;
@@ -14,6 +15,8 @@ use directories::ProjectDirs;
 use serde::Deserialize;
 use thiserror::Error;
 
+pub use crate::diagnostics::DiagnosticSeverity;
+pub use crate::diagnostics::DiagnosticsConfig;
 pub use crate::tagspecs::ArgTypeDef;
 pub use crate::tagspecs::EndTagDef;
 pub use crate::tagspecs::IntermediateTagDef;
@@ -65,6 +68,8 @@ pub struct Settings {
     pythonpath: Vec<String>,
     #[serde(default)]
     tagspecs: Vec<TagSpecDef>,
+    #[serde(default)]
+    diagnostics: DiagnosticsConfig,
 }
 
 impl Settings {
@@ -86,6 +91,10 @@ impl Settings {
             if !overrides.tagspecs.is_empty() {
                 settings.tagspecs = overrides.tagspecs;
             }
+            // For diagnostics, override if the config is non-default
+            if overrides.diagnostics != DiagnosticsConfig::default() {
+                settings.diagnostics = overrides.diagnostics;
+            }
         }
 
         Ok(settings)
@@ -158,6 +167,11 @@ impl Settings {
     pub fn tagspecs(&self) -> &[TagSpecDef] {
         &self.tagspecs
     }
+
+    #[must_use]
+    pub fn diagnostics(&self) -> &DiagnosticsConfig {
+        &self.diagnostics
+    }
 }
 
 #[cfg(test)]
@@ -184,6 +198,7 @@ mod tests {
                     django_settings_module: None,
                     pythonpath: vec![],
                     tagspecs: vec![],
+                    diagnostics: DiagnosticsConfig::default(),
                 }
             );
         }
@@ -267,6 +282,42 @@ mod tests {
                 }
             );
         }
+
+        #[test]
+        fn test_load_diagnostics_config() {
+            let dir = tempdir().unwrap();
+            fs::write(
+                dir.path().join("djls.toml"),
+                r#"
+[diagnostics.severity]
+S100 = "off"
+S101 = "warning"
+"T" = "off"
+T100 = "hint"
+"#,
+            )
+            .unwrap();
+            let settings = Settings::new(Utf8Path::from_path(dir.path()).unwrap(), None).unwrap();
+            // Test via public API
+            assert_eq!(
+                settings.diagnostics.get_severity("S100"),
+                DiagnosticSeverity::Off
+            );
+            assert_eq!(
+                settings.diagnostics.get_severity("S101"),
+                DiagnosticSeverity::Warning
+            );
+            // T prefix applies to T900
+            assert_eq!(
+                settings.diagnostics.get_severity("T900"),
+                DiagnosticSeverity::Off
+            );
+            // T100 has specific override
+            assert_eq!(
+                settings.diagnostics.get_severity("T100"),
+                DiagnosticSeverity::Hint
+            );
+        }
     }
 
     mod priority {
diff --git a/crates/djls-ide/Cargo.toml b/crates/djls-ide/Cargo.toml
index 0521c527..38c7ea86 100644
--- a/crates/djls-ide/Cargo.toml
+++ b/crates/djls-ide/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.0.0"
 edition = "2021"
 
 [dependencies]
+djls-conf = { workspace = true }
 djls-project = { workspace = true }
 djls-semantic = { workspace = true }
 djls-source = { workspace = true }
diff --git a/crates/djls-ide/src/diagnostics.rs b/crates/djls-ide/src/diagnostics.rs
index 3916e87b..62e3d014 100644
--- a/crates/djls-ide/src/diagnostics.rs
+++ b/crates/djls-ide/src/diagnostics.rs
@@ -6,6 +6,7 @@ use djls_templates::TemplateError;
 use djls_templates::TemplateErrorAccumulator;
 use tower_lsp_server::lsp_types;
 
+use crate::ext::DiagnosticSeverityExt;
 use crate::ext::SpanExt;
 
 trait DiagnosticError: std::fmt::Display {
@@ -88,6 +89,9 @@ impl DiagnosticError for ValidationError {
 /// parsing and validation. The caller must provide the parsed `NodeList` (or `None`
 /// if parsing failed), making it explicit that parsing should have already occurred.
 ///
+/// Diagnostics are filtered based on the configuration settings (`select` and `ignore`),
+/// and severity levels can be overridden per diagnostic code.
+///
 /// # Parameters
 /// - `db`: The Salsa database
 /// - `file`: The source file (needed to retrieve accumulated template errors)
@@ -95,7 +99,7 @@ impl DiagnosticError for ValidationError {
 ///
 /// # Returns
 /// A vector of LSP diagnostics combining both template syntax errors and
-/// semantic validation errors.
+/// semantic validation errors, filtered by the diagnostics configuration.
 ///
 /// # Design
 /// This API design makes it clear that:
@@ -110,13 +114,27 @@ pub fn collect_diagnostics(
 ) -> Vec<lsp_types::Diagnostic> {
     let mut diagnostics = Vec::new();
 
+    let config = db.diagnostics_config();
+
     let template_errors =
         djls_templates::parse_template::accumulated::<TemplateErrorAccumulator>(db, file);
 
     let line_index = file.line_index(db);
 
     for error_acc in template_errors {
-        diagnostics.push(error_acc.0.as_diagnostic(line_index));
+        let mut diagnostic = error_acc.0.as_diagnostic(line_index);
+        if let Some(lsp_types::NumberOrString::String(code)) = &diagnostic.code {
+            let severity = config.get_severity(code);
+
+            // Skip if diagnostic is disabled (severity = off)
+            if let Some(lsp_severity) = severity.to_lsp_severity() {
+                diagnostic.severity = Some(lsp_severity);
+                diagnostics.push(diagnostic);
+            }
+        } else {
+            // No code, use default
+            diagnostics.push(diagnostic);
+        }
     }
 
     if let Some(nodelist) = nodelist {
@@ -125,9 +143,49 @@ pub fn collect_diagnostics(
         >(db, nodelist);
 
         for error_acc in validation_errors {
-            diagnostics.push(error_acc.0.as_diagnostic(line_index));
+            let mut diagnostic = error_acc.0.as_diagnostic(line_index);
+            if let Some(lsp_types::NumberOrString::String(code)) = &diagnostic.code {
+                let severity = config.get_severity(code);
+
+                // Skip if diagnostic is disabled (severity = off)
+                if let Some(lsp_severity) = severity.to_lsp_severity() {
+                    diagnostic.severity = Some(lsp_severity);
+                    diagnostics.push(diagnostic);
+                }
+            } else {
+                // No code, use default
+                diagnostics.push(diagnostic);
+            }
         }
     }
 
     diagnostics
 }
+
+#[cfg(test)]
+mod tests {
+    use djls_conf::DiagnosticSeverity;
+
+    use super::*;
+
+    #[test]
+    fn test_to_lsp_severity() {
+        assert_eq!(DiagnosticSeverity::Off.to_lsp_severity(), None);
+        assert_eq!(
+            DiagnosticSeverity::Error.to_lsp_severity(),
+            Some(lsp_types::DiagnosticSeverity::ERROR)
+        );
+        assert_eq!(
+            DiagnosticSeverity::Warning.to_lsp_severity(),
+            Some(lsp_types::DiagnosticSeverity::WARNING)
+        );
+        assert_eq!(
+            DiagnosticSeverity::Info.to_lsp_severity(),
+            Some(lsp_types::DiagnosticSeverity::INFORMATION)
+        );
+        assert_eq!(
+            DiagnosticSeverity::Hint.to_lsp_severity(),
+            Some(lsp_types::DiagnosticSeverity::HINT)
+        );
+    }
+}
diff --git a/crates/djls-ide/src/ext.rs b/crates/djls-ide/src/ext.rs
index 71d8e091..04e213fa 100644
--- a/crates/djls-ide/src/ext.rs
+++ b/crates/djls-ide/src/ext.rs
@@ -1,5 +1,6 @@
 use camino::Utf8Path;
 use camino::Utf8PathBuf;
+use djls_conf::DiagnosticSeverity;
 use djls_source::LineIndex;
 use djls_source::Offset;
 use djls_source::Span;
@@ -44,3 +45,19 @@ impl Utf8PathExt for Utf8PathBuf {
         lsp_types::Uri::from_file_path(self.as_std_path())
     }
 }
+
+pub(crate) trait DiagnosticSeverityExt {
+    fn to_lsp_severity(self) -> Option<lsp_types::DiagnosticSeverity>;
+}
+
+impl DiagnosticSeverityExt for DiagnosticSeverity {
+    fn to_lsp_severity(self) -> Option<lsp_types::DiagnosticSeverity> {
+        match self {
+            DiagnosticSeverity::Off => None,
+            DiagnosticSeverity::Error => Some(lsp_types::DiagnosticSeverity::ERROR),
+            DiagnosticSeverity::Warning => Some(lsp_types::DiagnosticSeverity::WARNING),
+            DiagnosticSeverity::Info => Some(lsp_types::DiagnosticSeverity::INFORMATION),
+            DiagnosticSeverity::Hint => Some(lsp_types::DiagnosticSeverity::HINT),
+        }
+    }
+}
diff --git a/crates/djls-semantic/src/blocks/tree.rs b/crates/djls-semantic/src/blocks/tree.rs
index 838c9f0a..eca7662b 100644
--- a/crates/djls-semantic/src/blocks/tree.rs
+++ b/crates/djls-semantic/src/blocks/tree.rs
@@ -247,6 +247,10 @@ mod tests {
         fn template_dirs(&self) -> Option<Vec<Utf8PathBuf>> {
             None
         }
+
+        fn diagnostics_config(&self) -> djls_conf::DiagnosticsConfig {
+            djls_conf::DiagnosticsConfig::default()
+        }
     }
 
     #[test]
diff --git a/crates/djls-semantic/src/db.rs b/crates/djls-semantic/src/db.rs
index 10807452..653ab106 100644
--- a/crates/djls-semantic/src/db.rs
+++ b/crates/djls-semantic/src/db.rs
@@ -1,4 +1,5 @@
 use camino::Utf8PathBuf;
+use djls_conf::DiagnosticsConfig;
 use djls_templates::Db as TemplateDb;
 
 use crate::blocks::TagIndex;
@@ -13,6 +14,9 @@ pub trait Db: TemplateDb {
     fn tag_index(&self) -> TagIndex<'_>;
 
     fn template_dirs(&self) -> Option<Vec<Utf8PathBuf>>;
+
+    /// Get the diagnostics configuration
+    fn diagnostics_config(&self) -> DiagnosticsConfig;
 }
 
 #[salsa::accumulator]
diff --git a/crates/djls-semantic/src/semantic/forest.rs b/crates/djls-semantic/src/semantic/forest.rs
index 3d08e723..3e578b8c 100644
--- a/crates/djls-semantic/src/semantic/forest.rs
+++ b/crates/djls-semantic/src/semantic/forest.rs
@@ -287,6 +287,10 @@ mod tests {
         fn template_dirs(&self) -> Option<Vec<Utf8PathBuf>> {
             None
         }
+
+        fn diagnostics_config(&self) -> djls_conf::DiagnosticsConfig {
+            djls_conf::DiagnosticsConfig::default()
+        }
     }
 
     #[test]
diff --git a/crates/djls-server/src/db.rs b/crates/djls-server/src/db.rs
index 06c70a1d..c2b5b501 100644
--- a/crates/djls-server/src/db.rs
+++ b/crates/djls-server/src/db.rs
@@ -199,6 +199,10 @@ impl SemanticDb for DjangoDatabase {
             None
         }
     }
+
+    fn diagnostics_config(&self) -> djls_conf::DiagnosticsConfig {
+        self.settings().diagnostics().clone()
+    }
 }
 
 #[salsa::db]
diff --git a/docs/configuration.md b/docs/configuration.md
index 7aa7e2d3..c54ce2f2 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -55,6 +55,110 @@ Additional directories to add to Python's import search path when the inspector
 
 Enable debug logging for troubleshooting language server issues.
 
+### `diagnostics`
+
+Configure diagnostic severity levels. All diagnostics are enabled by default at "error" severity level.
+
+**Default:** All diagnostics shown as errors
+
+#### `diagnostics.severity`
+
+Map diagnostic codes or prefixes to severity levels. Supports:
+- **Exact codes:** `"S100"`, `"T100"`
+- **Prefixes:** `"S"` (all S-series), `"T"` (all T-series), `"S1"` (S100-S199), `"T9"` (T900-T999)
+- **Resolution:** More specific patterns override less specific (exact > longer prefix > shorter prefix)
+
+**Available severity levels:**
+- `"off"` - Disable diagnostic completely
+- `"hint"` - Show as subtle hint
+- `"info"` - Show as information
+- `"warning"` - Show as warning
+- `"error"` - Show as error (default)
+
+#### Available Diagnostic Codes
+
+**Template Errors (T-series):**
+- `T100` - Parser errors (syntax issues in templates)
+- `T900` - IO errors (file read/write issues)
+- `T901` - Configuration errors (invalid tagspecs)
+
+**Semantic Validation Errors (S-series):**
+- `S100` - Unclosed tag (missing end tag)
+- `S101` - Unbalanced structure (mismatched block tags)
+- `S102` - Orphaned tag (intermediate tag without parent)
+- `S103` - Unmatched block name (e.g., `{% endblock foo %}` doesn't match `{% block bar %}`)
+- `S104` - Missing required arguments
+- `S105` - Too many arguments
+- `S106` - Invalid literal argument
+- `S107` - Invalid argument choice
+
+#### Examples
+
+**Disable specific diagnostics:**
+```toml
+[diagnostics.severity]
+S100 = "off"  # Don't show unclosed tag errors
+T100 = "off"  # Don't show parser errors
+```
+
+**Disable all template errors:**
+```toml
+[diagnostics.severity]
+"T" = "off"  # Prefix matches all T-series
+```
+
+**Disable with specific override:**
+```toml
+[diagnostics.severity]
+"T" = "off"     # Disable all template errors
+T100 = "hint"   # But show parser errors as hints (specific overrides prefix)
+```
+
+**Make all semantic errors warnings:**
+```toml
+[diagnostics.severity]
+"S" = "warning"  # All semantic errors as warnings
+```
+
+**Complex configuration:**
+```toml
+[diagnostics.severity]
+# Disable all template errors
+"T" = "off"
+
+# But show parser errors as hints
+T100 = "hint"
+
+# Make all semantic errors warnings
+"S" = "warning"
+
+# Except completely disable unclosed tags
+S100 = "off"
+
+# And make S10x (S100-S109) info level
+"S10" = "info"
+```
+
+**Resolution order example:**
+```toml
+[diagnostics.severity]
+"S" = "warning"    # Base: all S-series are warnings
+"S1" = "info"      # Override: S100-S199 are info
+S100 = "off"       # Override: S100 is off
+
+# Results:
+# S100 → off (exact match)
+# S101 → info ("S1" prefix)
+# S200 → warning ("S" prefix)
+```
+
+**When to configure:**
+
+- Disable false positives: Set problematic diagnostics to `"off"`
+- Gradual adoption: Downgrade to `"warning"` or `"hint"` during migration
+- Focus attention: Disable entire categories with prefix patterns
+- Fine-tune experience: Mix prefix patterns with specific overrides
+
 ### `tagspecs`
 
 **Default:** `[]`
@@ -80,7 +184,15 @@ Pass configuration through your editor's LSP client using `initializationOptions
 {
   "django_settings_module": "myproject.settings",
   "venv_path": "/path/to/venv",
-  "pythonpath": ["/path/to/shared/libs"]
+  "pythonpath": ["/path/to/shared/libs"],
+  "diagnostics": {
+    "severity": {
+      "S100": "off",
+      "S101": "warning",
+      "T": "off",
+      "T100": "hint"
+    }
+  }
 }
 ```
 
@@ -97,6 +209,12 @@ If you use `pyproject.toml`, add a `[tool.djls]` section:
 django_settings_module = "myproject.settings"
 venv_path = "/path/to/venv"  # Optional: only if auto-detection fails
 pythonpath = ["/path/to/shared/libs"]  # Optional: additional import paths
+
+[tool.djls.diagnostics.severity]
+S100 = "off"
+S101 = "warning"
+"T" = "off"
+T100 = "hint"
 ```
 
 If you prefer a dedicated config file or don't use `pyproject.toml`, you can use `djls.toml` (same settings, no `[tool.djls]` table).