diff --git a/libass/ass.h b/libass/ass.h
index 92d4142624..851be6681d 100644
--- a/libass/ass.h
+++ b/libass/ass.h
@@ -21,6 +21,7 @@
 #ifndef LIBASS_ASS_H
 #define LIBASS_ASS_H
 
+#include <stdio.h>
 #include "ass_types.h"
 
 /// Libass renderer object. Contents are private.
diff --git a/libass/ass_bitmap.h b/libass/ass_bitmap.h
index 12a5da0ab1..634d7e41b1 100644
--- a/libass/ass_bitmap.h
+++ b/libass/ass_bitmap.h
@@ -21,6 +21,9 @@
 #ifndef LIBASS_BITMAP_H
 #define LIBASS_BITMAP_H
 
+#include <ft2build.h>
+#include FT_GLYPH_H
+
 typedef struct ass_synth_priv_s ass_synth_priv_t;
 
 ass_synth_priv_t* ass_synth_init(void);
diff --git a/libass/ass_cache.h b/libass/ass_cache.h
index e0a220bb74..289753ef67 100644
--- a/libass/ass_cache.h
+++ b/libass/ass_cache.h
@@ -21,6 +21,10 @@
 #ifndef LIBASS_CACHE_H
 #define LIBASS_CACHE_H
 
+#include "ass.h"
+#include "ass_font.h"
+#include "ass_bitmap.h"
+
 void ass_font_cache_init(void);
 ass_font_t* ass_font_cache_find(ass_font_desc_t* desc);
 void* ass_font_cache_add(ass_font_t* font);
diff --git a/libass/ass_font.h b/libass/ass_font.h
index 53cda0ad43..cafdc65771 100644
--- a/libass/ass_font.h
+++ b/libass/ass_font.h
@@ -21,6 +21,12 @@
 #ifndef LIBASS_FONT_H
 #define LIBASS_FONT_H
 
+#include <stdint.h>
+#include <ft2build.h>
+#include FT_GLYPH_H
+#include "ass.h"
+#include "ass_types.h"
+
 typedef struct ass_font_desc_s {
 	char* family;
 	unsigned bold;
diff --git a/libass/ass_fontconfig.h b/libass/ass_fontconfig.h
index 9e0eca371b..3806f2468b 100644
--- a/libass/ass_fontconfig.h
+++ b/libass/ass_fontconfig.h
@@ -21,6 +21,11 @@
 #ifndef LIBASS_FONTCONFIG_H
 #define LIBASS_FONTCONFIG_H
 
+#include <stdint.h>
+#include "ass_types.h"
+#include <ft2build.h>
+#include FT_FREETYPE_H
+
 #ifdef HAVE_FONTCONFIG
 #include <fontconfig/fontconfig.h>
 #endif
diff --git a/libass/ass_mp.h b/libass/ass_mp.h
index be98dc7a82..6ef3540289 100644
--- a/libass/ass_mp.h
+++ b/libass/ass_mp.h
@@ -22,6 +22,8 @@
 #define LIBASS_MP_H
 
 #include "subreader.h"
+#include "ass_types.h"
+#include "ass.h"
 
 extern ass_library_t* ass_library;
 extern int ass_enabled;
diff --git a/libass/ass_types.h b/libass/ass_types.h
index cf39846e67..23e1074129 100644
--- a/libass/ass_types.h
+++ b/libass/ass_types.h
@@ -21,6 +21,8 @@
 #ifndef LIBASS_TYPES_H
 #define LIBASS_TYPES_H
 
+#include <stdint.h>
+
 #define VALIGN_SUB 0
 #define VALIGN_CENTER 8
 #define VALIGN_TOP 4
diff --git a/libass/ass_utils.h b/libass/ass_utils.h
index f574409783..7d6ffb681b 100644
--- a/libass/ass_utils.h
+++ b/libass/ass_utils.h
@@ -21,6 +21,8 @@
 #ifndef LIBASS_UTILS_H
 #define LIBASS_UTILS_H
 
+#include <stdint.h>
+
 int mystrtoi(char** p, int base, int* res);
 int mystrtou32(char** p, int base, uint32_t* res);
 int mystrtod(char** p, double* res);