diff --git a/usr.bin/csplit/csplit.1 b/usr.bin/csplit/csplit.1
index 61526eae601e..84ca52c330c5 100644
--- a/usr.bin/csplit/csplit.1
+++ b/usr.bin/csplit/csplit.1
@@ -115,6 +115,17 @@ After all the patterns have been processed, the remaining input data
 .Pp
 Requesting to split at a line before the current line number or past the
 end of the file will result in an error.
+.Sh ENVIRONMENT
+The
+.Ev LANG ,
+.Ev LC_ALL ,
+.Ev LC_COLLATE
+and
+.Ev LC_CTYPE
+environment variables affect the execution of
+.Nm
+as described in
+.Xr environ 7 .
 .Sh EXAMPLES
 Split the
 .Xr mdoc 7
diff --git a/usr.bin/csplit/csplit.c b/usr.bin/csplit/csplit.c
index f54a489937a5..5513f7b83f61 100644
--- a/usr.bin/csplit/csplit.c
+++ b/usr.bin/csplit/csplit.c
@@ -51,6 +51,7 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <errno.h>
 #include <limits.h>
+#include <locale.h>
 #include <regex.h>
 #include <signal.h>
 #include <stdint.h>
@@ -99,6 +100,8 @@ main(int argc, char *argv[])
 	char *ep, *p;
 	FILE *ofp;
 
+	setlocale(LC_ALL, "");
+
 	kflag = sflag = 0;
 	prefix = "xx";
 	sufflen = 2;