diff --git a/.woodpecker/clang-tidy-checks b/.woodpecker/clang-tidy-checks
index 67394d4..3c6c62e 100644
--- a/.woodpecker/clang-tidy-checks
+++ b/.woodpecker/clang-tidy-checks
@@ -1,6 +1,7 @@
 # checks
 clang-analyzer-*,clang-diagnostic-*,bugprone-*,performance-*,modernize-*
 misc-*,readability-*,android-cloexec-*,cert-*
+llvm-include-order
 
 # silence
 -misc-unused-parameters
diff --git a/autoreload.c b/autoreload.c
index 47751d5..c4b5665 100644
--- a/autoreload.c
+++ b/autoreload.c
@@ -23,8 +23,8 @@
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 #include <sys/inotify.h>
+#include <unistd.h>
 
 static union {
 	char d[4096]; /* aligned buffer */
diff --git a/commands.c b/commands.c
index 8a73462..8741a26 100644
--- a/commands.c
+++ b/commands.c
@@ -19,14 +19,14 @@
 
 #include "nsxiv.h"
 
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/wait.h>
-
 #include "commands.h"
 
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
 extern img_t img;
 extern tns_t tns;
 extern win_t win;
diff --git a/main.c b/main.c
index 10f7440..a6c4187 100644
--- a/main.c
+++ b/main.c
@@ -22,22 +22,23 @@
 #include "commands.h"
 #include "config.h"
 
-#include <stdlib.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <locale.h>
+#include <poll.h>
+#include <signal.h>
 #include <stdarg.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <errno.h>
-#include <locale.h>
-#include <signal.h>
-#include <poll.h>
 #include <sys/stat.h>
+#include <sys/time.h>
 #include <sys/wait.h>
 #include <time.h>
-#include <sys/time.h>
-#include <X11/keysym.h>
+#include <unistd.h>
+
 #include <X11/XF86keysym.h>
+#include <X11/keysym.h>
 
 #define MODMASK(mask) ((mask) & USED_MODMASK)
 #define BAR_SEP "  "
diff --git a/nsxiv.h b/nsxiv.h
index eb06328..7d81fff 100644
--- a/nsxiv.h
+++ b/nsxiv.h
@@ -20,8 +20,9 @@
 #ifndef NSXIV_H
 #define NSXIV_H
 
-#include <stddef.h>
 #include <stdbool.h>
+#include <stddef.h>
+
 #include <Imlib2.h>
 #include <X11/Xlib.h>
 
diff --git a/options.c b/options.c
index 8fade87..69b45b9 100644
--- a/options.c
+++ b/options.c
@@ -20,8 +20,8 @@
 #include "nsxiv.h"
 #include "version.h"
 
-#include <stdlib.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
diff --git a/util.c b/util.c
index 31ab4b8..65c39e5 100644
--- a/util.c
+++ b/util.c
@@ -20,13 +20,13 @@
 #include "nsxiv.h"
 
 #include <assert.h>
-#include <stdlib.h>
+#include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
-#include <errno.h>
 
 const char *progname;
 
diff --git a/window.c b/window.c
index 3cfa188..f472474 100644
--- a/window.c
+++ b/window.c
@@ -22,13 +22,14 @@
 #include "config.h"
 #include "icon/data.h"
 
+#include <locale.h>
 #include <stdlib.h>
 #include <string.h>
-#include <locale.h>
 #include <unistd.h>
-#include <X11/cursorfont.h>
+
 #include <X11/Xatom.h>
 #include <X11/Xresource.h>
+#include <X11/cursorfont.h>
 
 #if HAVE_LIBFONTS
 #include "utf8.h"