diff --git a/sys/conf/files b/sys/conf/files
index 9171b434a7bf..53f90f7afc22 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -4099,28 +4099,32 @@ libkern/strtouq.c		standard
 libkern/strvalid.c		standard
 libkern/timingsafe_bcmp.c	standard
 contrib/zlib/adler32.c		optional crypto | geom_uzip | \
-	mxge | ddb_ctf | gzio | zfs | zlib
+	mxge | ddb_ctf | gzio | zfs | zlib \
+	compile-with "${NORMAL_C} -Wno-deprecated-non-prototype"
 contrib/zlib/compress.c		optional crypto | geom_uzip | \
 	mxge | ddb_ctf | gzio | zfs | zlib \
-	compile-with "${NORMAL_C} -Wno-cast-qual"
+	compile-with "${NORMAL_C} -Wno-cast-qual -Wno-deprecated-non-prototype"
 contrib/zlib/crc32.c		optional crypto | geom_uzip | \
 	mxge | ddb_ctf | gzio | zfs | zlib \
 	compile-with "${NORMAL_C} ${NO_WSTRICT_PROTOTYPES}"
 contrib/zlib/deflate.c		optional crypto | geom_uzip | \
 	mxge | ddb_ctf | gzio | zfs | zlib \
-	compile-with "${NORMAL_C} -Wno-cast-qual"
+	compile-with "${NORMAL_C} -Wno-cast-qual -Wno-deprecated-non-prototype"
 contrib/zlib/inffast.c		optional crypto | geom_uzip | \
-	mxge | ddb_ctf | gzio | zfs | zlib
+	mxge | ddb_ctf | gzio | zfs | zlib \
+	compile-with "${NORMAL_C} -Wno-deprecated-non-prototype"
 contrib/zlib/inflate.c		optional crypto | geom_uzip | \
-	mxge | ddb_ctf | gzio | zfs | zlib
+	mxge | ddb_ctf | gzio | zfs | zlib \
+	compile-with "${NORMAL_C} -Wno-deprecated-non-prototype"
 contrib/zlib/inftrees.c		optional crypto | geom_uzip | \
-	mxge | ddb_ctf | gzio | zfs | zlib
+	mxge | ddb_ctf | gzio | zfs | zlib \
+	compile-with "${NORMAL_C} -Wno-deprecated-non-prototype"
 contrib/zlib/trees.c		optional crypto | geom_uzip | \
 	mxge | ddb_ctf | gzio | zfs | zlib \
 	compile-with "${NORMAL_C} ${NO_WSTRICT_PROTOTYPES}"
 contrib/zlib/uncompr.c		optional crypto | geom_uzip | \
 	mxge | ddb_ctf | gzio | zfs | zlib \
-	compile-with "${NORMAL_C} -Wno-cast-qual"
+	compile-with "${NORMAL_C} -Wno-cast-qual -Wno-deprecated-non-prototype"
 contrib/zlib/zutil.c		optional crypto | geom_uzip | \
 	mxge | ddb_ctf | gzio | zfs | zlib \
 	compile-with "${NORMAL_C} ${NO_WSTRICT_PROTOTYPES}"
diff --git a/sys/modules/zlib/Makefile b/sys/modules/zlib/Makefile
index 6391255e512b..178d3a3f7ab7 100644
--- a/sys/modules/zlib/Makefile
+++ b/sys/modules/zlib/Makefile
@@ -25,4 +25,6 @@ CWARNFLAGS.crc32.c+=${NO_WSTRICT_PROTOTYPES} # crc32.c:586
 CWARNFLAGS.trees.c+=${NO_WSTRICT_PROTOTYPES} # trees.c:232
 CWARNFLAGS.zutil.c+=${NO_WSTRICT_PROTOTYPES} # zutil.c:27,32
 
+CWARNFLAGS+=-Wno-deprecated-non-prototype
+
 .include <bsd.kmod.mk>