diff --git a/src/common/color/convert-color.ts b/src/common/color/convert-color.ts
index f325aef1fd..f6bbcd2c24 100644
--- a/src/common/color/convert-color.ts
+++ b/src/common/color/convert-color.ts
@@ -144,7 +144,7 @@ export function theme2hex(themeColor: string): string {
     return themeColor;
   }
 
-  const rgbFromColorName = colors[themeColor];
+  const rgbFromColorName = colors[themeColor.toLowerCase()];
   if (rgbFromColorName) {
     return rgb2hex(rgbFromColorName);
   }
diff --git a/test/common/color/convert-color.test.ts b/test/common/color/convert-color.test.ts
index 57907f764b..adcd846781 100644
--- a/test/common/color/convert-color.test.ts
+++ b/test/common/color/convert-color.test.ts
@@ -48,6 +48,7 @@ describe("Color Conversion Tests", () => {
 
   it("should convert theme color to hex (ignoring alpha)", () => {
     expect(theme2hex("red")).toBe("#ff0000");
+    expect(theme2hex("ReD")).toBe("#ff0000");
     expect(theme2hex("#ff0000")).toBe("#ff0000");
     expect(theme2hex("unicorn")).toBe("unicorn");
     expect(theme2hex("#abc")).toBe("#aabbcc");