diff --git a/sys/include/net/gnrc/tcp/config.h b/sys/include/net/gnrc/tcp/config.h
index 5953090cf1..c4aa11beb6 100644
--- a/sys/include/net/gnrc/tcp/config.h
+++ b/sys/include/net/gnrc/tcp/config.h
@@ -68,11 +68,11 @@ extern "C" {
 /**
  * @brief Maximum Segment Size (MSS).
  */
-#ifndef GNRC_TCP_MSS
+#ifndef CONFIG_GNRC_TCP_MSS
 #ifdef  MODULE_GNRC_IPV6
-#define GNRC_TCP_MSS (1220U) /**< If IPv6 is used. Get MSS = 1280 - IPv6 Hdr - TCP Hdr = 1220 */
+#define CONFIG_GNRC_TCP_MSS (1220U) /**< If IPv6 is used. Get MSS = 1280 - IPv6 Hdr - TCP Hdr = 1220 */
 #else
-#define GNRC_TCP_MSS (576U) /**< Default MSS */
+#define CONFIG_GNRC_TCP_MSS (576U) /**< Default MSS */
 #endif
 #endif
 
@@ -87,7 +87,7 @@ extern "C" {
  * @brief Default receive window size
  */
 #ifndef GNRC_TCP_DEFAULT_WINDOW
-#define GNRC_TCP_DEFAULT_WINDOW (GNRC_TCP_MSS * CONFIG_GNRC_TCP_MSS_MULTIPLICATOR)
+#define GNRC_TCP_DEFAULT_WINDOW (CONFIG_GNRC_TCP_MSS * CONFIG_GNRC_TCP_MSS_MULTIPLICATOR)
 #endif
 
 /**
diff --git a/sys/net/gnrc/transport_layer/tcp/gnrc_tcp_fsm.c b/sys/net/gnrc/transport_layer/tcp/gnrc_tcp_fsm.c
index 29b61509f7..85a1a13199 100644
--- a/sys/net/gnrc/transport_layer/tcp/gnrc_tcp_fsm.c
+++ b/sys/net/gnrc/transport_layer/tcp/gnrc_tcp_fsm.c
@@ -272,7 +272,7 @@ static int _fsm_call_send(gnrc_tcp_tcb_t *tcb, void *buf, size_t len)
     /* Check if window is open and all packets were transmitted */
     if (payload > 0 && tcb->snd_wnd > 0 && tcb->pkt_retransmit == NULL) {
         /* Calculate segment size */
-        payload = (payload < GNRC_TCP_MSS) ? payload : GNRC_TCP_MSS;
+        payload = (payload < CONFIG_GNRC_TCP_MSS) ? payload : CONFIG_GNRC_TCP_MSS;
         payload = (payload < tcb->mss) ? payload : tcb->mss;
         payload = (payload < len) ? payload : len;
 
@@ -307,8 +307,8 @@ static int _fsm_call_recv(gnrc_tcp_tcb_t *tcb, void *buf, size_t len)
     /* Read data into 'buf' up to 'len' bytes from receive buffer */
     size_t rcvd = ringbuffer_get(&(tcb->rcv_buf), buf, len);
 
-    /* If receive buffer can store more than GNRC_TCP_MSS: open window to available buffer size */
-    if (ringbuffer_get_free(&tcb->rcv_buf) >= GNRC_TCP_MSS) {
+    /* If receive buffer can store more than CONFIG_GNRC_TCP_MSS: open window to available buffer size */
+    if (ringbuffer_get_free(&tcb->rcv_buf) >= CONFIG_GNRC_TCP_MSS) {
         tcb->rcv_wnd = ringbuffer_get_free(&(tcb->rcv_buf));
 
         /* Send ACK to anounce window update */
diff --git a/sys/net/gnrc/transport_layer/tcp/gnrc_tcp_pkt.c b/sys/net/gnrc/transport_layer/tcp/gnrc_tcp_pkt.c
index 984f8681bc..fdf8af54c6 100644
--- a/sys/net/gnrc/transport_layer/tcp/gnrc_tcp_pkt.c
+++ b/sys/net/gnrc/transport_layer/tcp/gnrc_tcp_pkt.c
@@ -201,7 +201,7 @@ int _pkt_build(gnrc_tcp_tcb_t *tcb, gnrc_pktsnip_t **out_pkt, uint16_t *seq_con,
 
             /* If SYN flag is set: Add MSS option */
             if (ctl & MSK_SYN) {
-                network_uint32_t mss_option = byteorder_htonl(_option_build_mss(GNRC_TCP_MSS));
+                network_uint32_t mss_option = byteorder_htonl(_option_build_mss(CONFIG_GNRC_TCP_MSS));
                 memcpy(opt_ptr, &mss_option, sizeof(mss_option));
             }
             /* Increase opt_ptr and decrease opt_left, if other options are added */