diff --git a/EtcTool/EtcSourceImage.cpp b/EtcTool/EtcSourceImage.cpp
index fcb1ac0..954fb0d 100644
--- a/EtcTool/EtcSourceImage.cpp
+++ b/EtcTool/EtcSourceImage.cpp
@@ -286,6 +286,26 @@ namespace Etc
 
 	}
 
+	// ----------------------------------------------------------------------------------------------------
+	// Flip the image in Y
+	void SourceImage::FlipY(void)
+	{
+		const size_t rowSizeBytes = sizeof(ColorFloatRGBA) * m_uiWidth;
+		char *pacRow = new char[rowSizeBytes];
+		assert(pacRow);
+
+		for (int iY = 0; iY < m_uiHeight / 2; ++iY)
+		{
+			ColorFloatRGBA *row1 = m_pafrgbaPixels + m_uiWidth * iY;
+			ColorFloatRGBA *row2 = m_pafrgbaPixels + m_uiWidth * (m_uiHeight - 1 - iY);
+			memcpy(pacRow, row1, rowSizeBytes);
+			memcpy(row1, row2, rowSizeBytes);
+			memcpy(row2, pacRow, rowSizeBytes);
+		}
+
+		delete [] pacRow;
+	}
+
 	// ----------------------------------------------------------------------------------------------------
 	//
 
diff --git a/EtcTool/EtcSourceImage.h b/EtcTool/EtcSourceImage.h
index 0e57e6e..8306d38 100644
--- a/EtcTool/EtcSourceImage.h
+++ b/EtcTool/EtcSourceImage.h
@@ -36,6 +36,7 @@ namespace Etc
 		void SetName(const char *a_pstrFilename);
 
 		void NormalizeXYZ(void);
+		void FlipY(void);
 
 		inline const char *GetFilename(void)
 		{
diff --git a/EtcTool/EtcTool.cpp b/EtcTool/EtcTool.cpp
index 1b52778..e2b1ab7 100644
--- a/EtcTool/EtcTool.cpp
+++ b/EtcTool/EtcTool.cpp
@@ -90,6 +90,7 @@ class Commands
 		i_vPixel = -1;
 		verboseOutput = false;
 		boolNormalizeXYZ = false;
+		boolFlipY = false;
 		mipmaps = 1;
 		mipFilterFlags = Etc::FILTER_WRAP_NONE;
 	}
@@ -114,6 +115,7 @@ class Commands
 	int i_hPixel;
 	int i_vPixel;
 	bool boolNormalizeXYZ;
+	bool boolFlipY;
 	int mipmaps;
 	unsigned int mipFilterFlags;
 };
@@ -152,6 +154,10 @@ int main(int argc, const char * argv[])
 	{
 		sourceimage.NormalizeXYZ();
 	}
+	if (commands.boolFlipY)
+	{
+		sourceimage.FlipY();
+	}
 
 	unsigned int uiSourceWidth = sourceimage.GetWidth();
 	unsigned int uiSourceHeight = sourceimage.GetHeight();
@@ -628,6 +634,11 @@ bool Commands::ProcessCommandLineArguments(int a_iArgs, const char *a_apstrArgs[
 		{
 			boolNormalizeXYZ = true;
 		}
+		else if (strcmp(a_apstrArgs[iArg], "-flipy") == 0 ||
+				 strcmp(a_apstrArgs[iArg], "-flipY") == 0)
+		{
+			boolFlipY = true;
+		}
 		else if (strcmp(a_apstrArgs[iArg], "-output") == 0)
 		{
 			++iArg;
@@ -800,6 +811,7 @@ void Commands::PrintUsageMessage(void)
 	printf("    -help                         prints this message\n");
 	printf("    -jobs or -j <thread_count>    specifies the number of threads (default=1)\n");
 	printf("    -normalizexyz                 normalize RGB to have a length of 1\n");
+	printf("    -flipy                        flip the image vertically\n");
 	printf("    -verbose or -v                shows status information during the encoding\n");
 	printf("                                  process\n");
 	printf("    -mipmaps or -m <mip_count>    sets the maximum number of mipaps to generate (default=1)\n");