diff --git a/esphome/components/wifi/__init__.py b/esphome/components/wifi/__init__.py
index a701aa37e5..13d698d245 100644
--- a/esphome/components/wifi/__init__.py
+++ b/esphome/components/wifi/__init__.py
@@ -169,6 +169,7 @@ def _validate(config):
         config[CONF_NETWORKS] = cv.ensure_list(WIFI_NETWORK_STA)(network)
 
     if (CONF_NETWORKS not in config) and (CONF_AP not in config):
+        config = config.copy()
         config[CONF_NETWORKS] = []
 
     if config.get(CONF_FAST_CONNECT, False):