diff --git a/esphome/components/socket/bsd_sockets_impl.h b/esphome/components/socket/bsd_sockets_impl.h
index 6700227b1eb..6e2af08ab40 100644
--- a/esphome/components/socket/bsd_sockets_impl.h
+++ b/esphome/components/socket/bsd_sockets_impl.h
@@ -59,7 +59,7 @@ class BSDSocketImpl {
 #if defined(USE_LWIP_FAST_SELECT) && defined(CONFIG_LWIP_TCPIP_CORE_LOCKING)
     // Fast path for TCP_NODELAY: directly set the pcb flag under the TCPIP core lock,
     // bypassing lwip_setsockopt overhead (socket lookups, hook, switch cascade, refcounting).
-    if (level == IPPROTO_TCP && optname == TCP_NODELAY && optlen == sizeof(int)) {
+    if (level == IPPROTO_TCP && optname == TCP_NODELAY && optlen == sizeof(int) && optval != nullptr) {
       LwIPLock lock;
       if (esphome_lwip_set_nodelay(this->cached_sock_, *reinterpret_cast<const int *>(optval) != 0))
         return 0;
diff --git a/esphome/components/socket/lwip_sockets_impl.h b/esphome/components/socket/lwip_sockets_impl.h
index 94f4d29229c..6ab4ecf2ee5 100644
--- a/esphome/components/socket/lwip_sockets_impl.h
+++ b/esphome/components/socket/lwip_sockets_impl.h
@@ -55,7 +55,7 @@ class LwIPSocketImpl {
 #if defined(USE_LWIP_FAST_SELECT) && defined(CONFIG_LWIP_TCPIP_CORE_LOCKING)
     // Fast path for TCP_NODELAY: directly set the pcb flag under the TCPIP core lock,
     // bypassing lwip_setsockopt overhead (socket lookups, hook, switch cascade, refcounting).
-    if (level == IPPROTO_TCP && optname == TCP_NODELAY && optlen == sizeof(int)) {
+    if (level == IPPROTO_TCP && optname == TCP_NODELAY && optlen == sizeof(int) && optval != nullptr) {
       LwIPLock lock;
       if (esphome_lwip_set_nodelay(this->cached_sock_, *reinterpret_cast<const int *>(optval) != 0))
         return 0;
diff --git a/esphome/core/lwip_fast_select.c b/esphome/core/lwip_fast_select.c
index b1d54b01a6c..ca693494670 100644
--- a/esphome/core/lwip_fast_select.c
+++ b/esphome/core/lwip_fast_select.c
@@ -220,6 +220,8 @@ void esphome_lwip_hook_socket(struct lwip_sock *sock) {
 bool esphome_lwip_set_nodelay(struct lwip_sock *sock, bool enable) {
   if (sock == NULL || sock->conn == NULL || sock->conn->pcb.tcp == NULL)
     return false;
+  if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_TCP)
+    return false;
   if (enable) {
     tcp_nagle_disable(sock->conn->pcb.tcp);
   } else {
diff --git a/esphome/core/lwip_fast_select.h b/esphome/core/lwip_fast_select.h
index bcb3dc04f78..50706ba9f69 100644
--- a/esphome/core/lwip_fast_select.h
+++ b/esphome/core/lwip_fast_select.h
@@ -70,7 +70,7 @@ void esphome_lwip_wake_main_loop_from_isr(int *px_higher_priority_task_woken);
 /// Must be called with the TCPIP core lock held (LwIPLock in C++).
 /// This bypasses lwip_setsockopt() overhead (socket lookups, switch cascade,
 /// hooks, refcounting) — just a direct pcb->flags bit set/clear.
-/// Returns true if successful, false if sock/conn/pcb is NULL.
+/// Returns true if successful, false if sock/conn/pcb is NULL or the socket is not TCP.
 bool esphome_lwip_set_nodelay(struct lwip_sock *sock, bool enable);
 
 /// Wake the main loop task from any context (ISR, thread, or main loop).