diff --git a/Cargo.lock b/Cargo.lock
index bfb9aa31..a155e50c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -234,6 +234,7 @@ dependencies = [
  "ron",
  "rust-ini",
  "serde",
+ "serde-untagged",
  "serde_derive",
  "serde_json",
  "snapbox",
@@ -357,6 +358,16 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
 
+[[package]]
+name = "erased-serde"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e004d887f51fcb9fef17317a2f3525c887d8aa3f4f50fed920816a688284a5b7"
+dependencies = [
+ "serde",
+ "typeid",
+]
+
 [[package]]
 name = "errno"
 version = "0.3.5"
@@ -1345,18 +1356,18 @@ checksum = "dc375e1527247fe1a97d8b7156678dfe7c1af2fc075c9a4db3690ecd2a148068"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.69"
+version = "1.0.97"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "134c189feb4956b20f6f547d2cf727d4c0fe06722b20a0eec87ed445a97f92da"
+checksum = "d61789d7719defeb74ea5fe81f2fdfdbd28a803847077cecce2ff14e1472f6f1"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.33"
+version = "1.0.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5267fca4496028628a95160fc423a33e8b2e6af8a5302579e322e4b520293cae"
+checksum = "1885c039570dc00dcb4ff087a89e185fd56bae234ddc7f056a945bf36467248d"
 dependencies = [
  "proc-macro2",
 ]
@@ -1619,18 +1630,29 @@ dependencies = [
 
 [[package]]
 name = "serde"
-version = "1.0.189"
+version = "1.0.219"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8e422a44e74ad4001bdc8eede9a4570ab52f71190e9c076d14369f38b9200537"
+checksum = "5f0e2c6ed6606019b4e29e69dbaba95b11854410e5347d525002456dbbb786b6"
 dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde-untagged"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34836a629bcbc6f1afdf0907a744870039b1e14c0561cb26094fa683b158eff3"
+dependencies = [
+ "erased-serde",
+ "serde",
+ "typeid",
+]
+
 [[package]]
 name = "serde_derive"
-version = "1.0.189"
+version = "1.0.219"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e48d1f918009ce3145511378cf68d613e3b3d9137d67272562080d68a2b32d5"
+checksum = "5b0276cf7f2c73365f7157c8123c21cd9a50fbbd844757af28ca1f5925fc2a00"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1769,9 +1791,9 @@ checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
 
 [[package]]
 name = "syn"
-version = "2.0.38"
+version = "2.0.104"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e96b79aaa137db8f61e26363a0c9b47d8b4ec75da28b7d1d614c2303e232408b"
+checksum = "17b6f705963418cdb9927482fa304bc562ece2fdd4f616084c50b7023b435a40"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2056,6 +2078,12 @@ dependencies = [
  "utf-8",
 ]
 
+[[package]]
+name = "typeid"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc7d623258602320d5c55d1bc22793b57daff0ec7efc270ea7d55ce1d5f5471c"
+
 [[package]]
 name = "typenum"
 version = "1.17.0"
diff --git a/Cargo.toml b/Cargo.toml
index 59ac8873..063ba7e1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -125,7 +125,7 @@ default = ["toml", "json", "yaml", "ini", "ron", "json5", "convert-case", "async
 json = ["serde_json"]
 yaml = ["yaml-rust2"]
 ini = ["rust-ini"]
-json5 = ["json5_rs", "serde/derive"]
+json5 = ["json5_rs", "dep:serde-untagged"]
 convert-case = ["convert_case"]
 preserve_order = ["indexmap", "toml?/preserve_order", "serde_json?/preserve_order", "ron?/indexmap"]
 async = ["async-trait"]
@@ -145,6 +145,7 @@ indexmap = { version = "2.10.0", features = ["serde"], optional = true }
 convert_case = { version = "0.6", optional = true }
 pathdiff = "0.2"
 winnow = "0.7.0"
+serde-untagged = { version = "0.1.8", optional = true }
 
 [dev-dependencies]
 serde_derive = "1.0"
diff --git a/src/file/format/json5.rs b/src/file/format/json5.rs
index c0e557fc..56397e66 100644
--- a/src/file/format/json5.rs
+++ b/src/file/format/json5.rs
@@ -4,8 +4,7 @@ use crate::format;
 use crate::map::Map;
 use crate::value::{Value, ValueKind};
 
-#[derive(serde::Deserialize, Debug)]
-#[serde(untagged)]
+#[derive(Debug)]
 pub(crate) enum Val {
     Null,
     Boolean(bool),
@@ -16,6 +15,23 @@ pub(crate) enum Val {
     Object(Map<String, Self>),
 }
 
+impl<'de> serde::de::Deserialize<'de> for Val {
+    fn deserialize<D>(d: D) -> Result<Self, D::Error>
+    where
+        D: serde::de::Deserializer<'de>,
+    {
+        serde_untagged::UntaggedEnumVisitor::new()
+            .bool(|value| Ok(Self::Boolean(value)))
+            .i64(|value| Ok(Self::Integer(value)))
+            .f64(|value| Ok(Self::Float(value)))
+            .string(|value| Ok(Val::String(value.to_owned())))
+            .none(|| Ok(Self::Null))
+            .seq(|value| value.deserialize().map(Val::Array))
+            .map(|value| value.deserialize().map(Val::Object))
+            .deserialize(d)
+    }
+}
+
 pub(crate) fn parse(
     uri: Option<&String>,
     text: &str,
diff --git a/src/ser.rs b/src/ser.rs
index 46b90e45..041938be 100644
--- a/src/ser.rs
+++ b/src/ser.rs
@@ -676,8 +676,6 @@ impl ser::SerializeStructVariant for Unreachable {
 
 #[cfg(test)]
 mod test {
-    use serde::{Deserialize, Serialize};
-    #[cfg(not(feature = "json5"))]
     use serde_derive::{Deserialize, Serialize};
 
     use super::*;