diff --git a/makefile.unix b/makefile.unix
index b4a6d869..0f8cf311 100644
--- a/makefile.unix
+++ b/makefile.unix
@@ -171,6 +171,7 @@ HDRS_INSTALLED = \
     src/webp/demux.h \
     src/webp/encode.h \
     src/webp/mux.h \
+    src/webp/mux_types.h \
     src/webp/types.h \
 
 HDRS = \
@@ -194,7 +195,6 @@ HDRS = \
     src/utils/rescaler.h \
     src/utils/thread.h \
     src/webp/format_constants.h \
-    src/webp/mux_types.h \
     $(HDRS_INSTALLED) \
 
 OUT_LIBS = examples/libexample_util.a src/libwebpdecoder.a src/libwebp.a
diff --git a/src/demux/Makefile.am b/src/demux/Makefile.am
index 2e0a4dcb..d1f126e5 100644
--- a/src/demux/Makefile.am
+++ b/src/demux/Makefile.am
@@ -6,6 +6,7 @@ libwebpdemux_la_SOURCES += demux.c
 
 libwebpdemuxinclude_HEADERS =
 libwebpdemuxinclude_HEADERS += ../webp/demux.h
+libwebpdemuxinclude_HEADERS += ../webp/mux_types.h
 libwebpdemuxinclude_HEADERS += ../webp/types.h
 
 libwebpdemux_la_LIBADD = ../libwebp.la
diff --git a/src/mux/Makefile.am b/src/mux/Makefile.am
index c94586a8..19b033d3 100644
--- a/src/mux/Makefile.am
+++ b/src/mux/Makefile.am
@@ -9,6 +9,7 @@ libwebpmux_la_SOURCES += muxread.c
 
 libwebpmuxinclude_HEADERS =
 libwebpmuxinclude_HEADERS += ../webp/mux.h
+libwebpmuxinclude_HEADERS += ../webp/mux_types.h
 libwebpmuxinclude_HEADERS += ../webp/types.h
 
 libwebpmux_la_LIBADD = ../libwebp.la