diff --git a/CHANGES b/CHANGES
index 711386a17..d1b02e314 100644
--- a/CHANGES
+++ b/CHANGES
@@ -180,7 +180,7 @@ Version 0.96 [May, 1997]
   Fixed serious bug with < 8bpp images introduced in 0.95
   Fixed 256-color transparency bug (Greg Roelofs)
   Fixed up documentation (Greg Roelofs, Laszlo Nyul)
-  Fixed "error" in pngconf.h for Linux setjmp() behaviour
+  Fixed "error" in pngconf.h for Linux setjmp() behavior
   Fixed DOS medium model support (Tim Wegner)
   Fixed png_check_keyword() for case with error in static string text
   Added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
@@ -204,8 +204,8 @@ Version 0.97 [January, 1998]
   Added more conditions for png_do_background, to avoid changing
     black pixels to background when a background is supplied and
     no pixels are transparent
-  Repaired PNG_NO_STDIO behaviour
-  Tested NODIV support and made it default behaviour (Greg Roelofs)
+  Repaired PNG_NO_STDIO behavior
+  Tested NODIV support and made it default behavior (Greg Roelofs)
   Added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
   Regularized version numbering scheme and bumped shared-library major
      version number to 2 to avoid problems with libpng 0.89 apps (Greg Roelofs)
diff --git a/png.c b/png.c
index f85c90e42..db3051d17 100644
--- a/png.c
+++ b/png.c
@@ -43,7 +43,7 @@ png_set_sig_bytes(png_structp png_ptr, int num_bytes)
  * can simply check the remaining bytes for extra assurance.  Returns
  * an integer less than, equal to, or greater than zero if sig is found,
  * respectively, to be less than, to match, or be greater than the correct
- * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
+ * PNG signature (this is the same behavior as strcmp, memcmp, etc).
  */
 int PNGAPI
 png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
diff --git a/png.h b/png.h
index 85331b3c1..a1245c8a5 100644
--- a/png.h
+++ b/png.h
@@ -2304,7 +2304,7 @@ PNG_EXPORT(171, void, png_set_sCAL_s,
    handling or default unknown chunk handling is not desired.  Any chunks not
    listed will be handled in the default manner.  The IHDR and IEND chunks
    must not be listed.
-      keep = 0: follow default behaviour
+      keep = 0: follow default behavior
            = 1: do not keep
            = 2: keep only if safe-to-copy
            = 3: keep even if unsafe-to-copy