diff --git a/GPU/Directx9/PixelShaderGeneratorDX9.cpp b/GPU/Directx9/PixelShaderGeneratorDX9.cpp
index 73bd6165e4..7539dfa4e9 100644
--- a/GPU/Directx9/PixelShaderGeneratorDX9.cpp
+++ b/GPU/Directx9/PixelShaderGeneratorDX9.cpp
@@ -135,7 +135,8 @@ bool GenerateFragmentShaderHLSL(const FShaderID &id, char *buffer, ShaderLanguag
 	if (doTexture) {
 		WRITE(p, "  float3 v_texcoord: TEXCOORD0;\n");
 	}
-	WRITE(p, "  float4 v_color0: COLOR0;\n");
+	const char *colorInterpolation = doFlatShading && lang == HLSL_D3D11 ? "nointerpolation " : "";
+	WRITE(p, "  %sfloat4 v_color0: COLOR0;\n", colorInterpolation);
 	if (lmode) {
 		WRITE(p, "  float3 v_color1: COLOR1;\n");
 	}
diff --git a/GPU/Directx9/VertexShaderGeneratorDX9.cpp b/GPU/Directx9/VertexShaderGeneratorDX9.cpp
index 7b1b542558..227c51223c 100644
--- a/GPU/Directx9/VertexShaderGeneratorDX9.cpp
+++ b/GPU/Directx9/VertexShaderGeneratorDX9.cpp
@@ -231,7 +231,8 @@ void GenerateVertexShaderHLSL(const VShaderID &id, char *buffer, ShaderLanguage
 	if (doTexture) {
 		WRITE(p, "  float3 v_texcoord : TEXCOORD0;\n");
 	}
-	WRITE(p, "  float4 v_color0    : COLOR0;\n");
+	const char *colorInterpolation = doFlatShading && lang == HLSL_D3D11 ? "nointerpolation " : "";
+	WRITE(p, "  %sfloat4 v_color0    : COLOR0;\n", colorInterpolation);
 	if (lmode)
 		WRITE(p, "  float3 v_color1    : COLOR1;\n");