diff --git a/lib/liboath/Makefile.am b/lib/liboath/Makefile.am
index ef943e4..f313e6e 100644
--- a/lib/liboath/Makefile.am
+++ b/lib/liboath/Makefile.am
@@ -4,6 +4,8 @@ AM_CPPFLAGS = -I$(top_srcdir)/include -I$(top_srcdir)/lib/libpam
 
 lib_LTLIBRARIES = liboath.la
 
+noinst_HEADERS = oath_impl.h
+
 liboath_la_SOURCES = \
 	oath_base32.c \
 	oath_base64.c \