diff --git a/macros/src/types/enum.rs b/macros/src/types/enum.rs
index 2366e886..7f574de2 100644
--- a/macros/src/types/enum.rs
+++ b/macros/src/types/enum.rs
@@ -183,33 +183,33 @@ fn format_variant(
                 format!("{{ \"{}\": \"{}\", \"{}\": {} }}", #tag, #ts_name, #content, #parsed_ty)
             ),
         },
-        (false, Tagged::Internally { tag }) => match variant_type.inline_flattened {
-            Some(_) => {
-                quote! { #parsed_ty }
+        (false, Tagged::Internally { tag }) => match &variant.fields {
+            Fields::Unnamed(unnamed) if unnamed.unnamed.len() == 1 => {
+                let field = &unnamed.unnamed[0];
+                let field_attr = FieldAttr::from_attrs(&unnamed.unnamed[0].attrs)?;
+
+                field_attr.assert_validity(field)?;
+
+                if field_attr.skip {
+                    quote!(format!("{{ \"{}\": \"{}\" }}", #tag, #ts_name))
+                } else {
+                    let ty = match field_attr.type_override {
+                        Some(type_override) => quote! { #type_override },
+                        None => {
+                            let ty = field_attr.type_as(&field.ty);
+                            quote!(<#ty as #crate_rename::TS>::name(cfg))
+                        }
+                    };
+
+                    quote!(format!("{{ \"{}\": \"{}\" }} & {}", #tag, #ts_name, #ty))
+                }
             }
-            None => match &variant.fields {
-                Fields::Unnamed(unnamed) if unnamed.unnamed.len() == 1 => {
-                    let field = &unnamed.unnamed[0];
-                    let field_attr = FieldAttr::from_attrs(&unnamed.unnamed[0].attrs)?;
-
-                    field_attr.assert_validity(field)?;
-
-                    if field_attr.skip {
-                        quote!(format!("{{ \"{}\": \"{}\" }}", #tag, #ts_name))
-                    } else {
-                        let ty = match field_attr.type_override {
-                            Some(type_override) => quote! { #type_override },
-                            None => {
-                                let ty = field_attr.type_as(&field.ty);
-                                quote!(<#ty as #crate_rename::TS>::name(cfg))
-                            }
-                        };
-
-                        quote!(format!("{{ \"{}\": \"{}\" }} & {}", #tag, #ts_name, #ty))
-                    }
+            Fields::Unit => quote!(format!("{{ \"{}\": \"{}\" }}", #tag, #ts_name)),
+            _ => match variant_type.inline_flattened {
+                Some(_) => {
+                    quote! { #parsed_ty }
                 }
-                Fields::Unit => quote!(format!("{{ \"{}\": \"{}\" }}", #tag, #ts_name)),
-                _ => {
+                None => {
                     quote!(format!("{{ \"{}\": \"{}\" }} & {}", #tag, #ts_name, #parsed_ty))
                 }
             },
diff --git a/macros/src/types/newtype.rs b/macros/src/types/newtype.rs
index b4edb675..43a29b67 100644
--- a/macros/src/types/newtype.rs
+++ b/macros/src/types/newtype.rs
@@ -39,10 +39,15 @@ pub(crate) fn newtype(
         None => quote!(<#inner_ty as #crate_rename::TS>::name(cfg)),
     };
 
+    let inline_flattened = match field_attr.type_override {
+        Some(_) => None,
+        None => Some(quote!(<#inner_ty as #crate_rename::TS>::inline_flattened(cfg))),
+    };
+
     Ok(DerivedTS {
         crate_rename: crate_rename.clone(),
         inline: inline_def,
-        inline_flattened: None,
+        inline_flattened,
         docs: attr.docs.clone(),
         dependencies,
         export: attr.export,
diff --git a/macros/src/types/type_as.rs b/macros/src/types/type_as.rs
index 44d31793..50f35182 100644
--- a/macros/src/types/type_as.rs
+++ b/macros/src/types/type_as.rs
@@ -20,7 +20,7 @@ pub(crate) fn type_as_struct(
     Ok(DerivedTS {
         crate_rename: crate_rename.clone(),
         inline: quote!(<#type_as as #crate_rename::TS>::inline(cfg)),
-        inline_flattened: None,
+        inline_flattened: Some(quote!(<#type_as as #crate_rename::TS>::inline_flattened(cfg))),
         docs: attr.docs.clone(),
         dependencies,
         export: attr.export,
@@ -42,7 +42,7 @@ pub(crate) fn type_as_enum(attr: &EnumAttr, ts_name: Expr, type_as: &Type) -> Re
     Ok(DerivedTS {
         crate_rename: crate_rename.clone(),
         inline: quote!(<#type_as as #crate_rename::TS>::inline(cfg)),
-        inline_flattened: None,
+        inline_flattened: Some(quote!(<#type_as as #crate_rename::TS>::inline_flattened(cfg))),
         docs: attr.docs.clone(),
         dependencies,
         export: attr.export,
diff --git a/ts-rs/tests/integration/main.rs b/ts-rs/tests/integration/main.rs
index d2c85252..651e227d 100644
--- a/ts-rs/tests/integration/main.rs
+++ b/ts-rs/tests/integration/main.rs
@@ -45,6 +45,7 @@ mod lifetimes;
 mod list;
 mod merge_same_file_imports;
 mod nested;
+mod newtype_flatten;
 mod optional_field;
 mod path_bug;
 mod ranges;
@@ -69,6 +70,7 @@ mod top_level_type_as;
 mod top_level_type_override;
 mod tuple;
 mod type_as;
+mod type_as_flatten;
 mod type_override;
 mod union;
 mod union_named_serde_skip;
diff --git a/ts-rs/tests/integration/newtype_flatten.rs b/ts-rs/tests/integration/newtype_flatten.rs
new file mode 100644
index 00000000..56561d35
--- /dev/null
+++ b/ts-rs/tests/integration/newtype_flatten.rs
@@ -0,0 +1,58 @@
+#![allow(dead_code)]
+
+use ts_rs::{Config, TS};
+
+#[derive(TS)]
+#[ts(export, export_to = "newtype_flatten/")]
+struct Inner {
+    foo: String,
+    bar: i32,
+}
+
+#[derive(TS)]
+#[ts(export, export_to = "newtype_flatten/")]
+struct NewtypeWrapper(Inner);
+
+#[derive(TS)]
+#[ts(export, export_to = "newtype_flatten/")]
+struct Outer {
+    name: String,
+    #[ts(flatten)]
+    inner: NewtypeWrapper,
+}
+
+#[test]
+fn test_newtype_flatten() {
+    let cfg = Config::from_env();
+    assert_eq!(Inner::inline(&cfg), "{ foo: string, bar: number, }");
+    assert_eq!(NewtypeWrapper::inline(&cfg), "Inner");
+    assert_eq!(
+        Outer::inline(&cfg),
+        "{ name: string, foo: string, bar: number, }"
+    );
+}
+
+#[derive(TS)]
+#[ts(export, export_to = "newtype_flatten/")]
+struct InlinedNewtypeWrapper(#[ts(inline)] Inner);
+
+#[derive(TS)]
+#[ts(export, export_to = "newtype_flatten/")]
+struct OuterInlined {
+    name: String,
+    #[ts(flatten)]
+    inner: InlinedNewtypeWrapper,
+}
+
+#[test]
+fn test_newtype_flatten_inlined() {
+    let cfg = Config::from_env();
+    assert_eq!(
+        InlinedNewtypeWrapper::inline(&cfg),
+        "{ foo: string, bar: number, }"
+    );
+    assert_eq!(
+        OuterInlined::inline(&cfg),
+        "{ name: string, foo: string, bar: number, }"
+    );
+}
diff --git a/ts-rs/tests/integration/type_as_flatten.rs b/ts-rs/tests/integration/type_as_flatten.rs
new file mode 100644
index 00000000..3bec9835
--- /dev/null
+++ b/ts-rs/tests/integration/type_as_flatten.rs
@@ -0,0 +1,35 @@
+#![allow(dead_code)]
+
+use ts_rs::{Config, TS};
+
+#[derive(TS)]
+#[ts(export, export_to = "type_as_flatten/")]
+struct Substitute {
+    alpha: String,
+    beta: i32,
+}
+
+#[derive(TS)]
+#[ts(as = "Substitute")]
+#[ts(export, export_to = "type_as_flatten/")]
+struct TypeWithAs {
+    _internal: String,
+}
+
+#[derive(TS)]
+#[ts(export, export_to = "type_as_flatten/")]
+struct OuterWithTypeAs {
+    name: String,
+    #[ts(flatten)]
+    inner: TypeWithAs,
+}
+
+#[test]
+fn test_type_as_flatten() {
+    let cfg = Config::from_env();
+    assert_eq!(TypeWithAs::inline(&cfg), "{ alpha: string, beta: number, }");
+    assert_eq!(
+        OuterWithTypeAs::inline(&cfg),
+        "{ name: string, alpha: string, beta: number, }"
+    );
+}