diff --git a/Makefile b/Makefile
index 55d0d05..821fb9d 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ RENDER_OBJECTS = $(patsubst $(SRCDIR)/%.cpp, $(OBJDIR)/%.o, $(RENDER_SOURCES))
 ASSIMP_DIR=ext/assimp
 
 ifeq ($(USE_INTERNAL_ASSIMP), y)
-CXXFLAGS += -I$(ASSIMP_DIR)/include
+CXXFLAGS += -I$(ASSIMP_DIR)/include -I$(ASSIMP_DIR)/build/include
 ASSIMP_LIB := $(ASSIMP_DIR)/build/code/libassimp.a
 BUILD_ASSIMP_TARGET := build_assimp
 CLEAN_ASSIMP_TARGET := $(MAKE) -C $(ASSIMP_DIR)/build clean