diff --git a/common/gsm-sms.c b/common/gsm-sms.c
index 7c6aa02..36ebc08 100644
--- a/common/gsm-sms.c
+++ b/common/gsm-sms.c
@@ -434,7 +434,7 @@ static gn_error sms_data_decode(unsigned char *message, unsigned char *output, u
 	/* Unicode */
 	if ((dcs.type & 0x08) == 0x08) {
 		dprintf("Unicode message\n");
-		char_unicode_decode(output, message, length);
+		char_unicode_decode(output, message, 2 * length);
 	} else {
 		/* 8bit SMS */
 		if ((dcs.type & 0xf4) == 0xf4) {