diff --git a/src/bin/jp2/converttif.c b/src/bin/jp2/converttif.c
index dbda0741..c83d09ef 100644
--- a/src/bin/jp2/converttif.c
+++ b/src/bin/jp2/converttif.c
@@ -42,6 +42,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <ctype.h>
+#ifndef _WIN32
+#include <unistd.h>
+#endif
 
 #ifndef OPJ_HAVE_LIBTIFF
 # error OPJ_HAVE_LIBTIFF_NOT_DEFINED
diff --git a/tests/compare_images.c b/tests/compare_images.c
index b28d4957..e01603a7 100644
--- a/tests/compare_images.c
+++ b/tests/compare_images.c
@@ -37,6 +37,9 @@
 #include <string.h>
 #include <ctype.h>
 #include <assert.h>
+#ifndef _WIN32
+#include <unistd.h>
+#endif
 
 #include "opj_apps_config.h"
 #include "opj_getopt.h"