diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index ecb45ff6973f..e86d1dc65612 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -18732,7 +18732,7 @@ static void bgp_config_write_peer_global(struct vty *vty, struct bgp *bgp,
 	}
 
 	/* TCP max segment size */
-	if (CHECK_FLAG(peer->flags, PEER_FLAG_TCP_MSS))
+	if (peergroup_flag_check(peer, PEER_FLAG_TCP_MSS))
 		vty_out(vty, " neighbor %s tcp-mss %d\n", addr, peer->tcp_mss);
 
 	/* passive */
diff --git a/bgpd/bgpd.c b/bgpd/bgpd.c
index 22f1cf841426..d175a1f60fed 100644
--- a/bgpd/bgpd.c
+++ b/bgpd/bgpd.c
@@ -3031,6 +3031,10 @@ static void peer_group2peer_config_copy(struct peer_group *group,
 		bgp_peer_configure_bfd(peer, false);
 		bgp_peer_config_apply(peer, group);
 	}
+	/* peer tcp-mss */
+	if (!CHECK_FLAG(peer->flags_override, PEER_FLAG_TCP_MSS)) {
+		PEER_ATTR_INHERIT(peer, group, tcp_mss);
+	}
 }
 
 /* Peer group's remote AS configuration.  */
@@ -4763,40 +4767,42 @@ struct peer_flag_action {
 };
 
 static const struct peer_flag_action peer_flag_action_list[] = {
-	{PEER_FLAG_PASSIVE, 0, peer_change_reset},
-	{PEER_FLAG_SHUTDOWN, 0, peer_change_reset},
-	{PEER_FLAG_RTT_SHUTDOWN, 0, peer_change_none},
-	{PEER_FLAG_DONT_CAPABILITY, 0, peer_change_none},
-	{PEER_FLAG_OVERRIDE_CAPABILITY, 0, peer_change_none},
-	{PEER_FLAG_STRICT_CAP_MATCH, 0, peer_change_none},
-	{PEER_FLAG_DYNAMIC_CAPABILITY, 0, peer_change_none},
-	{PEER_FLAG_DISABLE_CONNECTED_CHECK, 0, peer_change_reset},
-	{PEER_FLAG_CAPABILITY_ENHE, 0, peer_change_reset},
-	{PEER_FLAG_ENFORCE_FIRST_AS, 0, peer_change_reset_in},
-	{PEER_FLAG_IFPEER_V6ONLY, 0, peer_change_reset},
-	{PEER_FLAG_ROUTEADV, 0, peer_change_none},
-	{PEER_FLAG_TIMER, 0, peer_change_none},
-	{PEER_FLAG_TIMER_CONNECT, 0, peer_change_none},
-	{PEER_FLAG_TIMER_DELAYOPEN, 0, peer_change_none},
-	{PEER_FLAG_PASSWORD, 0, peer_change_none},
-	{PEER_FLAG_LOCAL_AS, 0, peer_change_reset},
-	{PEER_FLAG_LOCAL_AS_NO_PREPEND, 0, peer_change_reset},
-	{PEER_FLAG_LOCAL_AS_REPLACE_AS, 0, peer_change_reset},
-	{PEER_FLAG_DUAL_AS, 0, peer_change_reset},
-	{PEER_FLAG_UPDATE_SOURCE, 0, peer_change_none},
-	{PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE, 0, peer_change_none},
-	{PEER_FLAG_EXTENDED_OPT_PARAMS, 0, peer_change_reset},
-	{PEER_FLAG_ROLE_STRICT_MODE, 0, peer_change_none},
-	{PEER_FLAG_ROLE, 0, peer_change_none},
-	{PEER_FLAG_PORT, 0, peer_change_reset},
-	{PEER_FLAG_AIGP, 0, peer_change_none},
-	{PEER_FLAG_GRACEFUL_SHUTDOWN, 0, peer_change_none},
-	{PEER_FLAG_CAPABILITY_SOFT_VERSION, 0, peer_change_none},
-	{PEER_FLAG_CAPABILITY_FQDN, 0, peer_change_none},
-	{PEER_FLAG_AS_LOOP_DETECTION, 0, peer_change_none},
-	{PEER_FLAG_EXTENDED_LINK_BANDWIDTH, 0, peer_change_none},
-	{PEER_FLAG_LONESOUL, 0, peer_change_reset_out},
-	{0, 0, 0}};
+	{ PEER_FLAG_PASSIVE, 0, peer_change_reset },
+	{ PEER_FLAG_SHUTDOWN, 0, peer_change_reset },
+	{ PEER_FLAG_RTT_SHUTDOWN, 0, peer_change_none },
+	{ PEER_FLAG_DONT_CAPABILITY, 0, peer_change_none },
+	{ PEER_FLAG_OVERRIDE_CAPABILITY, 0, peer_change_none },
+	{ PEER_FLAG_STRICT_CAP_MATCH, 0, peer_change_none },
+	{ PEER_FLAG_DYNAMIC_CAPABILITY, 0, peer_change_none },
+	{ PEER_FLAG_DISABLE_CONNECTED_CHECK, 0, peer_change_reset },
+	{ PEER_FLAG_CAPABILITY_ENHE, 0, peer_change_reset },
+	{ PEER_FLAG_ENFORCE_FIRST_AS, 0, peer_change_reset_in },
+	{ PEER_FLAG_IFPEER_V6ONLY, 0, peer_change_reset },
+	{ PEER_FLAG_ROUTEADV, 0, peer_change_none },
+	{ PEER_FLAG_TIMER, 0, peer_change_none },
+	{ PEER_FLAG_TIMER_CONNECT, 0, peer_change_none },
+	{ PEER_FLAG_TIMER_DELAYOPEN, 0, peer_change_none },
+	{ PEER_FLAG_PASSWORD, 0, peer_change_none },
+	{ PEER_FLAG_LOCAL_AS, 0, peer_change_reset },
+	{ PEER_FLAG_LOCAL_AS_NO_PREPEND, 0, peer_change_reset },
+	{ PEER_FLAG_LOCAL_AS_REPLACE_AS, 0, peer_change_reset },
+	{ PEER_FLAG_DUAL_AS, 0, peer_change_reset },
+	{ PEER_FLAG_UPDATE_SOURCE, 0, peer_change_none },
+	{ PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE, 0, peer_change_none },
+	{ PEER_FLAG_EXTENDED_OPT_PARAMS, 0, peer_change_reset },
+	{ PEER_FLAG_ROLE_STRICT_MODE, 0, peer_change_none },
+	{ PEER_FLAG_ROLE, 0, peer_change_none },
+	{ PEER_FLAG_PORT, 0, peer_change_reset },
+	{ PEER_FLAG_AIGP, 0, peer_change_none },
+	{ PEER_FLAG_GRACEFUL_SHUTDOWN, 0, peer_change_none },
+	{ PEER_FLAG_CAPABILITY_SOFT_VERSION, 0, peer_change_none },
+	{ PEER_FLAG_CAPABILITY_FQDN, 0, peer_change_none },
+	{ PEER_FLAG_AS_LOOP_DETECTION, 0, peer_change_none },
+	{ PEER_FLAG_EXTENDED_LINK_BANDWIDTH, 0, peer_change_none },
+	{ PEER_FLAG_LONESOUL, 0, peer_change_reset_out },
+	{ PEER_FLAG_TCP_MSS, 0, peer_change_none },
+	{ 0, 0, 0 }
+};
 
 static const struct peer_flag_action peer_af_flag_action_list[] = {
 	{PEER_FLAG_SEND_COMMUNITY, 1, peer_change_reset_out},
@@ -6097,8 +6103,24 @@ void peer_port_unset(struct peer *peer)
  */
 void peer_tcp_mss_set(struct peer *peer, uint32_t tcp_mss)
 {
+	struct peer *member;
+	struct listnode *node, *nnode;
+
+	peer_flag_set(peer, PEER_FLAG_TCP_MSS);
 	peer->tcp_mss = tcp_mss;
-	SET_FLAG(peer->flags, PEER_FLAG_TCP_MSS);
+
+	if (!CHECK_FLAG(peer->sflags, PEER_STATUS_GROUP))
+		return;
+
+	for (ALL_LIST_ELEMENTS(peer->group->peer, node, nnode, member)) {
+		/* Skip peers with overridden configuration. */
+		if (CHECK_FLAG(member->flags_override, PEER_FLAG_TCP_MSS))
+			continue;
+
+		/* Set flag and configuration on peer-group member. */
+		SET_FLAG(member->flags, PEER_FLAG_TCP_MSS);
+		PEER_ATTR_INHERIT(member, peer->group, tcp_mss);
+	}
 	bgp_tcp_mss_set(peer);
 }
 
@@ -6108,8 +6130,37 @@ void peer_tcp_mss_set(struct peer *peer, uint32_t tcp_mss)
  */
 void peer_tcp_mss_unset(struct peer *peer)
 {
-	UNSET_FLAG(peer->flags, PEER_FLAG_TCP_MSS);
-	peer->tcp_mss = 0;
+	struct peer *member;
+	struct listnode *node, *nnode;
+
+	/* Inherit configuration from peer-group if peer is member. */
+	if (peer_group_active(peer)) {
+		peer_flag_inherit(peer, PEER_FLAG_TCP_MSS);
+		PEER_ATTR_INHERIT(peer, peer->group, tcp_mss);
+	} else {
+		/* Otherwise remove flag and configuration from peer. */
+		peer_flag_unset(peer, PEER_FLAG_TCP_MSS);
+		peer->tcp_mss = 0;
+	}
+
+	/* Skip peer-group mechanics for regular peers. */
+	if (!CHECK_FLAG(peer->sflags, PEER_STATUS_GROUP)) {
+		return;
+	}
+
+	/*
+	 * Remove flag and configuration from all peer-group members, unless
+	 * they are explicitely overriding peer-group configuration.
+	 */
+	for (ALL_LIST_ELEMENTS(peer->group->peer, node, nnode, member)) {
+		/* Skip peers with overridden configuration. */
+		if (CHECK_FLAG(member->flags_override, PEER_FLAG_TCP_MSS))
+			continue;
+
+		/* Remove flag and configuration on peer-group member. */
+		UNSET_FLAG(member->flags, PEER_FLAG_TCP_MSS);
+		member->tcp_mss = 0;
+	}
 	bgp_tcp_mss_set(peer);
 }