diff --git a/src/webgpu/shader/validation/statement/swizzle_assignment.spec.ts b/src/webgpu/shader/validation/statement/swizzle_assignment.spec.ts
new file mode 100644
index 000000000000..2c6978f6bf07
--- /dev/null
+++ b/src/webgpu/shader/validation/statement/swizzle_assignment.spec.ts
@@ -0,0 +1,105 @@
+export const description = `
+Validation tests for swizzle assignments.
+`;
+
+import { makeTestGroup } from '../../../../common/framework/test_group.js';
+import { ShaderValidationTest } from '../shader_validation_test.js';
+
+export const g = makeTestGroup(ShaderValidationTest);
+
+g.test('valid')
+  .desc('Valid swizzle assignments')
+  .params(u =>
+    u.combine('elemType', ['f32', 'i32', 'u32'] as const).combine('vecSize', [2, 3, 4] as const)
+  )
+  .fn(t => {
+    t.skipIfLanguageFeatureNotSupported('swizzle_assignment');
+    const { elemType, vecSize } = t.params;
+    const swizzle = 'xyzw'.substring(0, vecSize);
+    const vecType = `vec${swizzle.length}<${elemType}>`;
+    const code = `
+@fragment
+fn main() {
+  var v = vec4<${elemType}>(0);
+  v.${swizzle} = ${vecType}(1);
+}
+`;
+    t.expectCompileResult(true, code);
+  });
+
+g.test('invalid_lhs_not_reference')
+  .desc('Invalid swizzle assignment where LHS is not a reference')
+  .params(u => u.combine('lhs', ['vec4f()', 'const_vec', 'foo()']))
+  .fn(t => {
+    t.skipIfLanguageFeatureNotSupported('swizzle_assignment');
+    const code = `
+const const_vec = vec4f();
+
+fn foo() -> vec4f {
+  return vec4f();
+}
+
+@fragment
+fn main() {
+  var v = vec4f();
+  ${t.params.lhs}.xyz = vec3(0.0);
+}
+`;
+    t.expectCompileResult(false, code);
+  });
+
+g.test('invalid_duplicate_components')
+  .desc('Invalid swizzle assignment with duplicate LHS components')
+  .fn(t => {
+    t.skipIfLanguageFeatureNotSupported('swizzle_assignment');
+    const code = `
+@fragment
+fn main() {
+  var v = vec4f();
+  v.xx = vec2f();
+}
+`;
+    t.expectCompileResult(false, code);
+  });
+
+g.test('invalid_component_mismatch')
+  .desc('Invalid swizzle assignment with mismatched number of components')
+  .fn(t => {
+    t.skipIfLanguageFeatureNotSupported('swizzle_assignment');
+    const code = `
+@fragment
+fn main() {
+  var v = vec4f();
+  v.xy = vec3f();
+}
+`;
+    t.expectCompileResult(false, code);
+  });
+
+g.test('invalid_component_oob')
+  .desc('Invalid swizzle assignment with components out of bounds')
+  .fn(t => {
+    t.skipIfLanguageFeatureNotSupported('swizzle_assignment');
+    const code = `
+@fragment
+fn main() {
+  var v = vec3f();
+  v.xyzw = vec4f();
+}
+`;
+    t.expectCompileResult(false, code);
+  });
+
+g.test('invalid_type_mismatch')
+  .desc('Invalid swizzle assignment with mismatched types')
+  .fn(t => {
+    t.skipIfLanguageFeatureNotSupported('swizzle_assignment');
+    const code = `
+@fragment
+fn main() {
+  var v = vec4f();
+  v.xy = vec2i();
+}
+`;
+    t.expectCompileResult(false, code);
+  });