diff --git a/libvips/iofuncs/generate.c b/libvips/iofuncs/generate.c
index bb3d1b2d7..8be7ad675 100644
--- a/libvips/iofuncs/generate.c
+++ b/libvips/iofuncs/generate.c
@@ -92,6 +92,11 @@
 #endif /*HAVE_CONFIG_H*/
 #include <glib/gi18n-lib.h>
 
+#if defined(_MSC_VER)
+#include <BaseTsd.h>
+typedef SSIZE_T ssize_t;
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
diff --git a/libvips/iofuncs/util.c b/libvips/iofuncs/util.c
index 047516084..c2049c107 100644
--- a/libvips/iofuncs/util.c
+++ b/libvips/iofuncs/util.c
@@ -37,6 +37,11 @@
 #endif /*HAVE_CONFIG_H*/
 #include <glib/gi18n-lib.h>
 
+#if defined(_MSC_VER)
+#include <BaseTsd.h>
+typedef SSIZE_T ssize_t;
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>