diff --git a/crypto/asn1/a_object.c b/crypto/asn1/a_object.c
index 4cca7a09e3045618075f1d07d852b3c507563e3e..463469d188bc5536809873c021a00105ee1a2d95 100644
--- a/crypto/asn1/a_object.c
+++ b/crypto/asn1/a_object.c
@@ -17,7 +17,7 @@
 #include "internal/asn1_int.h"
 #include "asn1_locl.h"
 
-int i2d_ASN1_OBJECT(ASN1_OBJECT *a, unsigned char **pp)
+int i2d_ASN1_OBJECT(const ASN1_OBJECT *a, unsigned char **pp)
 {
     unsigned char *p;
     int objsize;
@@ -161,12 +161,12 @@ int a2d_ASN1_OBJECT(unsigned char *out, int olen, const char *buf, int num)
     return (0);
 }
 
-int i2t_ASN1_OBJECT(char *buf, int buf_len, ASN1_OBJECT *a)
+int i2t_ASN1_OBJECT(char *buf, int buf_len, const ASN1_OBJECT *a)
 {
     return OBJ_obj2txt(buf, buf_len, a, 0);
 }
 
-int i2a_ASN1_OBJECT(BIO *bp, ASN1_OBJECT *a)
+int i2a_ASN1_OBJECT(BIO *bp, const ASN1_OBJECT *a)
 {
     char buf[80], *p = buf;
     int i;
diff --git a/doc/crypto/OBJ_nid2obj.pod b/doc/crypto/OBJ_nid2obj.pod
index 02e81bad34df7de7675aa9584dc0e18d1c2bcd72..3ada6679cf92b7d47e68e1532a562cdaa7a4ebbb 100644
--- a/doc/crypto/OBJ_nid2obj.pod
+++ b/doc/crypto/OBJ_nid2obj.pod
@@ -25,7 +25,7 @@ OBJ_dup, OBJ_txt2obj, OBJ_obj2txt, OBJ_create, OBJ_cleanup
  ASN1_OBJECT *OBJ_txt2obj(const char *s, int no_name);
  int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name);
 
- int i2t_ASN1_OBJECT(char *buf, int buf_len, ASN1_OBJECT *a);
+ int i2t_ASN1_OBJECT(char *buf, int buf_len, const ASN1_OBJECT *a);
 
  int OBJ_cmp(const ASN1_OBJECT *a, const ASN1_OBJECT *b);
  ASN1_OBJECT *OBJ_dup(const ASN1_OBJECT *o);
diff --git a/include/openssl/asn1.h b/include/openssl/asn1.h
index 03fc21e7d56a53eabb5176a65fe33eb1fdd6883a..3655bf5c605fe294f8755c303646efdbd89ebb23 100644
--- a/include/openssl/asn1.h
+++ b/include/openssl/asn1.h
@@ -526,7 +526,7 @@ void *ASN1_TYPE_unpack_sequence(const ASN1_ITEM *it, const ASN1_TYPE *t);
 
 ASN1_OBJECT *ASN1_OBJECT_new(void);
 void ASN1_OBJECT_free(ASN1_OBJECT *a);
-int i2d_ASN1_OBJECT(ASN1_OBJECT *a, unsigned char **pp);
+int i2d_ASN1_OBJECT(const ASN1_OBJECT *a, unsigned char **pp);
 ASN1_OBJECT *d2i_ASN1_OBJECT(ASN1_OBJECT **a, const unsigned char **pp,
                              long length);
 
@@ -632,10 +632,10 @@ int i2a_ASN1_INTEGER(BIO *bp, ASN1_INTEGER *a);
 int a2i_ASN1_INTEGER(BIO *bp, ASN1_INTEGER *bs, char *buf, int size);
 int i2a_ASN1_ENUMERATED(BIO *bp, ASN1_ENUMERATED *a);
 int a2i_ASN1_ENUMERATED(BIO *bp, ASN1_ENUMERATED *bs, char *buf, int size);
-int i2a_ASN1_OBJECT(BIO *bp, ASN1_OBJECT *a);
+int i2a_ASN1_OBJECT(BIO *bp, const ASN1_OBJECT *a);
 int a2i_ASN1_STRING(BIO *bp, ASN1_STRING *bs, char *buf, int size);
 int i2a_ASN1_STRING(BIO *bp, ASN1_STRING *a, int type);
-int i2t_ASN1_OBJECT(char *buf, int buf_len, ASN1_OBJECT *a);
+int i2t_ASN1_OBJECT(char *buf, int buf_len, const ASN1_OBJECT *a);
 
 int a2d_ASN1_OBJECT(unsigned char *out, int olen, const char *buf, int num);
 ASN1_OBJECT *ASN1_OBJECT_create(int nid, unsigned char *data, int len,