diff --git a/aegisub/build/aegisub_vs2008/compiler_options.vsprops b/aegisub/build/aegisub_vs2008/compiler_options.vsprops
index 1d74de6e8..c9d9f1bf8 100644
--- a/aegisub/build/aegisub_vs2008/compiler_options.vsprops
+++ b/aegisub/build/aegisub_vs2008/compiler_options.vsprops
@@ -9,6 +9,7 @@
 		Optimization="1"
 		EnableIntrinsicFunctions="true"
 		FavorSizeOrSpeed="2"
+		AdditionalIncludeDirectories=""$(ProjectDir)../../src/include/""
 		RuntimeLibrary="2"
 		OpenMP="true"
 		WarningLevel="3"