diff --git a/esphome/components/esp32/preferences.cpp b/esphome/components/esp32/preferences.cpp
index 240b834b8d..08439746b6 100644
--- a/esphome/components/esp32/preferences.cpp
+++ b/esphome/components/esp32/preferences.cpp
@@ -23,7 +23,7 @@ struct NVSData {
   size_t len;
 
   void set_data(const uint8_t *src, size_t size) {
-    if (this->len != size) {
+    if (!this->data || this->len != size) {
       this->data = std::make_unique<uint8_t[]>(size);
       this->len = size;
     }
diff --git a/esphome/components/libretiny/preferences.cpp b/esphome/components/libretiny/preferences.cpp
index e08b4d6df3..68bc279767 100644
--- a/esphome/components/libretiny/preferences.cpp
+++ b/esphome/components/libretiny/preferences.cpp
@@ -22,7 +22,7 @@ struct NVSData {
   size_t len;
 
   void set_data(const uint8_t *src, size_t size) {
-    if (this->len != size) {
+    if (!this->data || this->len != size) {
       this->data = std::make_unique<uint8_t[]>(size);
       this->len = size;
     }