diff --git a/lib/otp/otp_parse.c b/lib/otp/otp_parse.c
index 85bbd6cff..f0fa3ed51 100644
--- a/lib/otp/otp_parse.c
+++ b/lib/otp/otp_parse.c
@@ -48,7 +48,7 @@ struct e {
   unsigned n;
 };
 
-static struct e inv_std_dict[] = {
+static const struct e inv_std_dict[] = {
 {"A", 0},
 {"ABE", 1},
 {"ABED", 571},
diff --git a/lib/otp/otp_print.c b/lib/otp/otp_print.c
index 064fd4158..b06b3a137 100644
--- a/lib/otp/otp_print.c
+++ b/lib/otp/otp_print.c
@@ -43,7 +43,7 @@ RCSID("$Id$");
 
 #include "otp_locl.h"
 
-static char *std_dict[] =
+static const char *std_dict[] =
 
 {        "A",    "ABE",   "ACE",   "ACT",   "AD",    "ADA",   "ADD",
 "AGO",   "AID",  "AIM",   "AIR",   "ALL",   "ALP",   "AM",    "AMY",