diff --git a/Texconv/texconv.cpp b/Texconv/texconv.cpp
index 5b4c7dc..5cb80b6 100644
--- a/Texconv/texconv.cpp
+++ b/Texconv/texconv.cpp
@@ -442,6 +442,7 @@ namespace
         { L"jpeg",  WIC_CODEC_JPEG },
         { L"png",   WIC_CODEC_PNG  },
         { L"dds",   CODEC_DDS      },
+        { L"ddx",   CODEC_DDS      },
         { L"tga",   CODEC_TGA      },
         { L"hdr",   CODEC_HDR      },
         { L"tif",   WIC_CODEC_TIFF },
@@ -2085,7 +2086,7 @@ int __cdecl wmain(_In_ int argc, _In_z_count_(argc) wchar_t* argv[])
             return 1;
         }
 
-        if (_wcsicmp(ext, L".dds") == 0)
+        if (_wcsicmp(ext, L".dds") == 0 || _wcsicmp(ext, L".ddx") == 0)
         {
             DDS_FLAGS ddsFlags = DDS_FLAGS_ALLOW_LARGE_FILES;
             if (dwOptions & (uint64_t(1) << OPT_DDS_DWORD_ALIGN))