diff --git a/libvips/foreign/magicksave.c b/libvips/foreign/magicksave.c
index e8afae64..fc32f8dc 100644
--- a/libvips/foreign/magicksave.c
+++ b/libvips/foreign/magicksave.c
@@ -143,12 +143,18 @@ vips_foreign_save_magick_next_image( VipsForeignSaveMagick *magick )
 		!vips_image_get_int( im, "gif-delay", &number ) )
 		image->delay = (size_t) number;
 
-	/* ImageMagick uses 0 to mean unset, so we must always add 1. See
-	 * coders/gif.c.
+	/* ImageMagick uses iterations like this (at least in gif save):
+	 * 	0 - set 0 loops (infinite)
+	 * 	1 - don't write the netscape extension block
+	 * 	2 - loop once
+	 * 	3 - loop twice etc.
+	 *
+	 * We have the simple gif meaning, so we must add one unless it's
+	 * zero.
 	 */
 	if( vips_image_get_typeof( im, "gif-loop" ) &&
 		!vips_image_get_int( im, "gif-loop", &number ) )
-		image->iterations = (size_t) (number + 1);
+		image->iterations = (size_t) (number ? number + 1 : 0);
 
 	if( vips_image_get_typeof( im, "gif-comment" ) &&
 		!vips_image_get_string( im, "gif-comment", &str ) )