diff --git a/liboctave/util/oct-locbuf.h b/liboctave/util/oct-locbuf.h
--- a/liboctave/util/oct-locbuf.h
+++ b/liboctave/util/oct-locbuf.h
@@ -98,7 +98,7 @@
   char *cnk;
 
   // Pointer to the beginning of the most recent allocation.
-  char *dat;
+  char *dat __attribute__ ((aligned (__BIGGEST_ALIGNMENT__)));
 
   // No copying!
   octave_chunk_buffer (const octave_chunk_buffer&);