diff --git a/ChangeLog.d/mbedtls_ssl_conf_alpn_protocols.txt b/ChangeLog.d/mbedtls_ssl_conf_alpn_protocols.txt
new file mode 100644
index 0000000000..0e396bbeff
--- /dev/null
+++ b/ChangeLog.d/mbedtls_ssl_conf_alpn_protocols.txt
@@ -0,0 +1,4 @@
+API changes
+   * The list passed to mbedtls_ssl_conf_alpn_protocols() is now declared
+     as having const elements, reflecting the fact that the library will
+     not modify it
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index c77cec88e3..60e58295a1 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1569,7 +1569,7 @@ struct mbedtls_ssl_config {
 #endif /* MBEDTLS_SSL_EARLY_DATA */
 
 #if defined(MBEDTLS_SSL_ALPN)
-    const char **MBEDTLS_PRIVATE(alpn_list);         /*!< ordered list of protocols          */
+    const char *const *MBEDTLS_PRIVATE(alpn_list); /*!< ordered list of protocols */
 #endif
 
 #if defined(MBEDTLS_SSL_DTLS_SRTP)
@@ -4011,7 +4011,8 @@ int mbedtls_ssl_set_hs_ecjpake_password_opaque(mbedtls_ssl_context *ssl,
  *
  * \return         0 on success, or MBEDTLS_ERR_SSL_BAD_INPUT_DATA.
  */
-int mbedtls_ssl_conf_alpn_protocols(mbedtls_ssl_config *conf, const char **protos);
+int mbedtls_ssl_conf_alpn_protocols(mbedtls_ssl_config *conf,
+                                    const char *const *protos);
 
 /**
  * \brief          Get the name of the negotiated Application Layer Protocol.
diff --git a/library/ssl_client.c b/library/ssl_client.c
index cb57a97669..307da0fabb 100644
--- a/library/ssl_client.c
+++ b/library/ssl_client.c
@@ -141,7 +141,7 @@ static int ssl_write_alpn_ext(mbedtls_ssl_context *ssl,
      *     ProtocolName protocol_name_list<2..2^16-1>
      * } ProtocolNameList;
      */
-    for (const char **cur = ssl->conf->alpn_list; *cur != NULL; cur++) {
+    for (const char *const *cur = ssl->conf->alpn_list; *cur != NULL; cur++) {
         /*
          * mbedtls_ssl_conf_set_alpn_protocols() checked that the length of
          * protocol names is less than 255.
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index f95f3c7c99..1c0aab0ac2 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2534,10 +2534,11 @@ void mbedtls_ssl_conf_sni(mbedtls_ssl_config *conf,
 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
 
 #if defined(MBEDTLS_SSL_ALPN)
-int mbedtls_ssl_conf_alpn_protocols(mbedtls_ssl_config *conf, const char **protos)
+int mbedtls_ssl_conf_alpn_protocols(mbedtls_ssl_config *conf,
+                                    const char *const *protos)
 {
     size_t cur_len, tot_len;
-    const char **p;
+    const char *const *p;
 
     /*
      * RFC 7301 3.1: "Empty strings MUST NOT be included and byte strings
@@ -5111,7 +5112,7 @@ static int ssl_context_load(mbedtls_ssl_context *ssl,
 #if defined(MBEDTLS_SSL_ALPN)
     {
         uint8_t alpn_len;
-        const char **cur;
+        const char *const *cur;
 
         if ((size_t) (end - p) < 1) {
             return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
@@ -8547,7 +8548,7 @@ int mbedtls_ssl_parse_alpn_ext(mbedtls_ssl_context *ssl,
     }
 
     /* Use our order of preference */
-    for (const char **alpn = ssl->conf->alpn_list; *alpn != NULL; alpn++) {
+    for (const char *const *alpn = ssl->conf->alpn_list; *alpn != NULL; alpn++) {
         size_t const alpn_len = strlen(*alpn);
         p = protocol_name_list;
         while (p < protocol_name_list_end) {
diff --git a/library/ssl_tls12_client.c b/library/ssl_tls12_client.c
index df7dfbfa61..ec778f9ed8 100644
--- a/library/ssl_tls12_client.c
+++ b/library/ssl_tls12_client.c
@@ -869,7 +869,7 @@ static int ssl_parse_alpn_ext(mbedtls_ssl_context *ssl,
                               const unsigned char *buf, size_t len)
 {
     size_t list_len, name_len;
-    const char **p;
+    const char *const *p;
 
     /* If we didn't send it, the server shouldn't send it */
     if (ssl->conf->alpn_list == NULL) {
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 9386801512..b7b075cc97 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -158,7 +158,7 @@ static int ssl_tls13_parse_alpn_ext(mbedtls_ssl_context *ssl,
 
     /* Check that the server chosen protocol was in our list and save it */
     MBEDTLS_SSL_CHK_BUF_READ_PTR(p, protocol_name_list_end, protocol_name_len);
-    for (const char **alpn = ssl->conf->alpn_list; *alpn != NULL; alpn++) {
+    for (const char *const *alpn = ssl->conf->alpn_list; *alpn != NULL; alpn++) {
         if (protocol_name_len == strlen(*alpn) &&
             memcmp(p, *alpn, protocol_name_len) == 0) {
             ssl->alpn_chosen = *alpn;