diff --git a/.clang-tidy b/.clang-tidy
index 532e020767..1dc5f3b8e5 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -7,7 +7,6 @@ Checks: "-*,\
           -bugprone-branch-clone,\
           -bugprone-copy-constructor-init,\
           -bugprone-easily-swappable-parameters,\
-          -bugprone-forward-declaration-namespace,\
           -bugprone-forwarding-reference-overload,\
           -bugprone-implicit-widening-of-multiplication-result,\
           -bugprone-lambda-function-name,\
diff --git a/src/dawn/native/opengl/GLFormat.h b/src/dawn/native/opengl/GLFormat.h
index ea3db9aa86..6d1d81e58e 100644
--- a/src/dawn/native/opengl/GLFormat.h
+++ b/src/dawn/native/opengl/GLFormat.h
@@ -20,8 +20,6 @@
 
 namespace dawn::native::opengl {
 
-class Device;
-
 struct GLFormat {
     GLenum internalFormat = 0;
     GLenum format = 0;
diff --git a/src/tint/ast/node.h b/src/tint/ast/node.h
index 41eeefe609..19d768228a 100644
--- a/src/tint/ast/node.h
+++ b/src/tint/ast/node.h
@@ -19,15 +19,6 @@
 
 #include "src/tint/clone_context.h"
 
-// Forward declarations
-namespace tint {
-class CloneContext;
-}  // namespace tint
-namespace tint::sem {
-class Type;
-class Info;
-}  // namespace tint::sem
-
 namespace tint::ast {
 
 /// AST base class node
diff --git a/src/tint/inspector/resource_binding.h b/src/tint/inspector/resource_binding.h
index 9a544357f9..6adab5a7fc 100644
--- a/src/tint/inspector/resource_binding.h
+++ b/src/tint/inspector/resource_binding.h
@@ -20,6 +20,11 @@
 #include "src/tint/ast/storage_texture.h"
 #include "src/tint/ast/texture.h"
 
+// Forward declarations
+namespace tint::sem {
+class Type;
+}  // namespace tint::sem
+
 namespace tint::inspector {
 
 /// Container for information about how a resource is bound
diff --git a/src/tint/sem/array.h b/src/tint/sem/array.h
index aeef3cedbe..7f72d8a8a1 100644
--- a/src/tint/sem/array.h
+++ b/src/tint/sem/array.h
@@ -21,11 +21,6 @@
 #include "src/tint/sem/node.h"
 #include "src/tint/sem/type.h"
 
-// Forward declarations
-namespace tint::ast {
-class Array;
-}  // namespace tint::ast
-
 namespace tint::sem {
 
 /// Array holds the semantic information for Array nodes.
diff --git a/src/tint/sem/block_statement.h b/src/tint/sem/block_statement.h
index e87b225246..4f12122dbd 100644
--- a/src/tint/sem/block_statement.h
+++ b/src/tint/sem/block_statement.h
@@ -24,7 +24,6 @@
 namespace tint::ast {
 class BlockStatement;
 class ContinueStatement;
-class Function;
 class Variable;
 }  // namespace tint::ast
 
diff --git a/src/tint/sem/module.h b/src/tint/sem/module.h
index a7b3d452fd..dffe003590 100644
--- a/src/tint/sem/module.h
+++ b/src/tint/sem/module.h
@@ -23,7 +23,6 @@
 // Forward declarations
 namespace tint::ast {
 class Node;
-class Module;
 }  // namespace tint::ast
 
 namespace tint::sem {
diff --git a/src/tint/sem/statement.h b/src/tint/sem/statement.h
index 741a3258f9..bdcb55c706 100644
--- a/src/tint/sem/statement.h
+++ b/src/tint/sem/statement.h
@@ -20,7 +20,6 @@
 
 // Forward declarations
 namespace tint::ast {
-class Function;
 class Statement;
 }  // namespace tint::ast
 namespace tint::sem {
diff --git a/src/tint/writer/glsl/generator.h b/src/tint/writer/glsl/generator.h
index 77a7f4b1bb..d48b0bc7d9 100644
--- a/src/tint/writer/glsl/generator.h
+++ b/src/tint/writer/glsl/generator.h
@@ -32,9 +32,6 @@
 namespace tint {
 class Program;
 }  // namespace tint
-namespace tint::writer::glsl {
-class GeneratorImpl;
-}  // namespace tint::writer::glsl
 
 namespace tint::writer::glsl {
 
diff --git a/src/tint/writer/hlsl/generator.h b/src/tint/writer/hlsl/generator.h
index f658c9949e..f14da6d113 100644
--- a/src/tint/writer/hlsl/generator.h
+++ b/src/tint/writer/hlsl/generator.h
@@ -30,9 +30,6 @@
 namespace tint {
 class Program;
 }  // namespace tint
-namespace tint::writer::hlsl {
-class GeneratorImpl;
-}  // namespace tint::writer::hlsl
 
 namespace tint::writer::hlsl {
 
diff --git a/src/tint/writer/msl/generator.h b/src/tint/writer/msl/generator.h
index 43b0cb7417..d4208cc262 100644
--- a/src/tint/writer/msl/generator.h
+++ b/src/tint/writer/msl/generator.h
@@ -28,9 +28,6 @@
 namespace tint {
 class Program;
 }  // namespace tint
-namespace tint::writer::msl {
-class GeneratorImpl;
-}  // namespace tint::writer::msl
 
 namespace tint::writer::msl {