diff --git a/bin/stty/modes.c b/bin/stty/modes.c
--- a/bin/stty/modes.c
+++ b/bin/stty/modes.c
@@ -128,6 +128,8 @@
 	{ "-decctlq",	IXANY, 0 },
 	{ "imaxbel",	IMAXBEL, 0 },
 	{ "-imaxbel",	0, IMAXBEL },
+	{ "iutf8",	IUTF8, 0 },
+	{ "-iutf8",	0, IUTF8 },
 	{ NULL,		0, 0 },
 };
 
diff --git a/bin/stty/print.c b/bin/stty/print.c
--- a/bin/stty/print.c
+++ b/bin/stty/print.c
@@ -129,6 +129,7 @@
 	put("-inpck", INPCK, 0);
 	put("-ignpar", IGNPAR, 0);
 	put("-parmrk", PARMRK, 0);
+	put("-iutf8", IUTF8, 1);
 
 	/* output flags */
 	tmp = tp->c_oflag;
diff --git a/sys/kern/tty.c b/sys/kern/tty.c
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -87,8 +87,8 @@
 /*
  * Flags that are supported and stored by this implementation.
  */
-#define TTYSUP_IFLAG	(IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|\
-			INLCR|IGNCR|ICRNL|IXON|IXOFF|IXANY|IMAXBEL)
+#define TTYSUP_IFLAG	(IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|INLCR|\
+			IGNCR|ICRNL|IXON|IXOFF|IXANY|IMAXBEL|IUTF8)
 #define TTYSUP_OFLAG	(OPOST|ONLCR|TAB3|ONOEOT|OCRNL|ONOCR|ONLRET)
 #define TTYSUP_LFLAG	(ECHOKE|ECHOE|ECHOK|ECHO|ECHONL|ECHOPRT|\
 			ECHOCTL|ISIG|ICANON|ALTWERASE|IEXTEN|TOSTOP|\
diff --git a/sys/sys/_termios.h b/sys/sys/_termios.h
--- a/sys/sys/_termios.h
+++ b/sys/sys/_termios.h
@@ -99,6 +99,7 @@
 #if __BSD_VISIBLE
 #define	IMAXBEL		0x00002000	/* ring bell on input queue full */
 #endif
+#define IUTF8		0x00004000	/* input is utf-8 encoded */
 
 /*
  * Output flags - software output processing