diff --git a/usr.bin/expand/expand.1 b/usr.bin/expand/expand.1
index 99d89a0a3af6..812691f348f6 100644
--- a/usr.bin/expand/expand.1
+++ b/usr.bin/expand/expand.1
@@ -95,6 +95,18 @@ are reconverted to maximal strings of tabs.  If the
 option is given, then tabs are inserted whenever they would compress the
 resultant file by replacing two or more characters.
 .El
+.Sh ENVIRONMENT
+The
+.Ev LANG ,
+.Ev LC_ALL
+and
+.Ev LC_CTYPE
+environment variables affect the execution of
+.Nm expand
+and
+.Nm unexpand
+as described in
+.Xr environ 7 .
 .Sh STANDARDS
 The
 .Nm expand
diff --git a/usr.bin/expand/expand.c b/usr.bin/expand/expand.c
index f83419df6bbd..e5a63c53215a 100644
--- a/usr.bin/expand/expand.c
+++ b/usr.bin/expand/expand.c
@@ -47,6 +47,7 @@ static const char rcsid[] =
 
 #include <ctype.h>
 #include <err.h>
+#include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -69,8 +70,11 @@ main(argc, argv)
 	register int n;
 	int rval;
 
+	setlocale(LC_CTYPE, "");
+
 	/* handle obsolete syntax */
-	while (argc > 1 && argv[1][0] == '-' && isdigit(argv[1][1])) {
+	while (argc > 1 && argv[1][0] == '-' &&
+	    isdigit((unsigned char)argv[1][1])) {
 		getstops(&argv[1][1]);
 		argc--; argv++;
 	}
@@ -140,7 +144,8 @@ main(argc, argv)
 
 			default:
 				putchar(c);
-				column++;
+				if (isprint(c))
+					column++;
 				continue;
 
 			case '\n':
@@ -173,7 +178,7 @@ getstops(cp)
 		tabstops[nstops++] = i;
 		if (*cp == 0)
 			break;
-		if (*cp != ',' && *cp != ' ')
+		if (*cp != ',' && !isblank((unsigned char)*cp))
 			errx(1, "bad tab stop spec");
 		cp++;
 	}
diff --git a/usr.bin/unexpand/unexpand.c b/usr.bin/unexpand/unexpand.c
index 37ba49c7d239..a1c565990a65 100644
--- a/usr.bin/unexpand/unexpand.c
+++ b/usr.bin/unexpand/unexpand.c
@@ -48,8 +48,10 @@ static const char sccsid[] = "@(#)unexpand.c	8.1 (Berkeley) 6/6/93";
 /*
  * unexpand - put tabs into a file replacing blanks
  */
+#include <ctype.h>
 #include <err.h>
 #include <limits.h>
+#include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -71,6 +73,8 @@ main(argc, argv)
 	int ch, failed;
 	char *filename;
 
+	setlocale(LC_CTYPE, "");
+
 	nstops = 1;
 	tabstops[0] = 8;
 	while ((ch = getopt(argc, argv, "at:")) != -1) {
@@ -176,7 +180,8 @@ tabify()
 			doneline = ocol = dcol = 0;
 		} else if (ch != ' ' || dcol > limit) {
 			putchar(ch);
-			ocol++, dcol++;
+			if (isprint(ch))
+				ocol++, dcol++;
 		}
 
 		/*
@@ -213,7 +218,7 @@ getstops(cp)
 		tabstops[nstops++] = i;
 		if (*cp == 0)
 			break;
-		if (*cp != ',' && *cp != ' ')
+		if (*cp != ',' && !isblank((unsigned char)*cp))
 			errx(1, "bad tab stop spec");
 		cp++;
 	}