diff --git a/Make.rules b/Make.rules
index 13e685da1bae56ffb58a1b5fcf0d5f3b1a7817f8..d87b435f5ff5da4ab6d16bbb19c5eeea859a6102 100644
--- a/Make.rules
+++ b/Make.rules
@@ -71,7 +71,7 @@ INSTALL		:= install
 INSTALLDIR	:= $(INSTALL) -d
 
 CFLAGS		?= -g -O2
-CFLAGS_ALL	:= -Wall -Wstrict-prototypes -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -std=gnu99 -fPIC
+CFLAGS_ALL	:= -Wall -Wstrict-prototypes -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -std=gnu11 -fPIC
 CFLAGS_ALL	+= $(CFLAGS)
 
 LDFLAGS		?= -g
diff --git a/meson.build b/meson.build
index 7827501e9b0cfdbb587ee385c072215e60f9f002..7f935f688b4ef30c165a9bfdf06aec8bb9fdd43d 100644
--- a/meson.build
+++ b/meson.build
@@ -1,7 +1,7 @@
 project(
 	'apk-tools',
 	['c'],
-	default_options : ['c_std=gnu99', 'optimization=2'],
+	default_options : ['c_std=gnu11', 'optimization=2'],
 	version: run_command('./get-version.sh', check: true).stdout().strip(),
 	meson_version: '>=0.55'
 )
diff --git a/src/adb.c b/src/adb.c
index fe614afad18873c3d661e82e78624a49437a9fa7..2781821c39bee36f0901f1f331d7a9e534086085 100644
--- a/src/adb.c
+++ b/src/adb.c
@@ -1,7 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <assert.h>
 #include <errno.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
diff --git a/src/apk.c b/src/apk.c
index c06801f0d648ace263a5a7fef4e1a69fc9055966..ee6f643aeb6daa2a7d37f6ba33a93744e9df95ec 100644
--- a/src/apk.c
+++ b/src/apk.c
@@ -11,7 +11,6 @@
 #include <fcntl.h>
 #include <ctype.h>
 #include <errno.h>
-#include <assert.h>
 #include <signal.h>
 #include <stdarg.h>
 #include <stdlib.h>
diff --git a/src/apk_crypto.h b/src/apk_crypto.h
index 18bf3b545c5ea575069c59b0948dc026bc4912ca..287d46f5df988106f84c3f82d4b3d891af16191e 100644
--- a/src/apk_crypto.h
+++ b/src/apk_crypto.h
@@ -9,7 +9,6 @@
 #ifndef APK_CRYPTO_H
 #define APK_CRYPTO_H
 
-#include <assert.h>
 #include <string.h>
 #include <openssl/evp.h>
 #include "apk_defines.h"
diff --git a/src/apk_defines.h b/src/apk_defines.h
index d4bab11d2367083e701556fa9e630f1c7258d076..4fd708b9c1564b3c004783995f39ac624df39e91 100644
--- a/src/apk_defines.h
+++ b/src/apk_defines.h
@@ -10,6 +10,7 @@
 #ifndef APK_DEFINES_H
 #define APK_DEFINES_H
 
+#include <assert.h>
 #include <endian.h>
 #include <stdint.h>
 #include <stddef.h>
diff --git a/src/app_mkpkg.c b/src/app_mkpkg.c
index 321a4e1231effb535bd030a25013c807da640b5b..2d9b9d70c53d5ae3426c1b164ee950f4c15dcfff 100644
--- a/src/app_mkpkg.c
+++ b/src/app_mkpkg.c
@@ -11,7 +11,6 @@
 #include <errno.h>
 #include <stdio.h>
 #include <fcntl.h>
-#include <assert.h>
 #include <unistd.h>
 #include <sys/stat.h>
 
diff --git a/src/commit.c b/src/commit.c
index 57c58417854a1bd14355fd83a964f2344e01b6eb..63ad94163d759188653282a72359472debc036d0 100644
--- a/src/commit.c
+++ b/src/commit.c
@@ -7,7 +7,6 @@
  * SPDX-License-Identifier: GPL-2.0-only
  */
 
-#include <assert.h>
 #include <limits.h>
 #include <stdint.h>
 #include <unistd.h>
diff --git a/src/print.c b/src/print.c
index dab98862fee8acedd5934d523411c1d65ca68b74..e20c708625ac2a96ba54fd8f31b3e322143c167e 100644
--- a/src/print.c
+++ b/src/print.c
@@ -7,7 +7,6 @@
  * SPDX-License-Identifier: GPL-2.0-only
  */
 
-#include <assert.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <stdlib.h>