diff --git a/include/net/net_core.h b/include/net/net_core.h
index 782499136a0..cc19d80535e 100644
--- a/include/net/net_core.h
+++ b/include/net/net_core.h
@@ -20,6 +20,8 @@
 #include <sys/__assert.h>
 #include <kernel.h>
 
+#include <net/net_timeout.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/include/net/net_timeout.h b/include/net/net_timeout.h
index 2cbc2934270..4ef08f5ebd5 100644
--- a/include/net/net_timeout.h
+++ b/include/net/net_timeout.h
@@ -28,6 +28,12 @@
 extern "C" {
 #endif
 
+/**
+ * Symbol to indicate that the caller wants the timeout to be waited forever.
+ * This can be used when a network API expects a millisecond timeout.
+ */
+#define NET_WAIT_FOREVER (-1)
+
 /** Let the max timeout be 100 ms lower because of
  * possible rounding in delayed work implementation.
  */