diff --git a/include/mbedtls/asn1.h b/include/mbedtls/asn1.h
index 3242699..825020f 100644
--- a/include/mbedtls/asn1.h
+++ b/include/mbedtls/asn1.h
@@ -209,6 +209,7 @@
 }
 mbedtls_asn1_named_data;
 
+#if defined(MBEDTLS_ASN1_PARSE_C) || defined(MBEDTLS_X509_CREATE_C)
 /**
  * \brief       Get the length of an ASN.1 element.
  *              Updates the pointer to immediately behind the length.
@@ -271,6 +272,9 @@
  * \return      An ASN.1 error code if the input does not start with
  *              a valid ASN.1 BOOLEAN.
  */
+#endif /* MBEDTLS_ASN1_PARSE_C || MBEDTLS_X509_CREATE_C */
+
+#if defined(MBEDTLS_ASN1_PARSE_C)
 int mbedtls_asn1_get_bool(unsigned char **p,
                           const unsigned char *end,
                           int *val);
@@ -645,4 +649,6 @@
 }
 #endif
 
+#endif /* MBEDTLS_ASN1_PARSE_C */
+
 #endif /* asn1.h */