diff --git a/esphome/components/api/api_connection.cpp b/esphome/components/api/api_connection.cpp
index bd62b4e31d..394c01bcab 100644
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -1112,24 +1112,31 @@ void APIConnection::on_get_time_response(const GetTimeResponse &value) {
   if (homeassistant::global_homeassistant_time != nullptr) {
     homeassistant::global_homeassistant_time->set_epoch_time(value.epoch_seconds);
 #ifdef USE_TIME_TIMEZONE
-    if (!value.timezone.empty()) {
+    // Only apply if the sender provided pre-parsed timezone data.
+    // Old clients (before 2026.3.0) only send the timezone string without the parsed struct,
+    // so all parsed_timezone fields default to zero — skip to keep the codegen-configured timezone.
+    // For actual UTC (all zeros), this also skips, which is harmless since UTC is the default.
+    // Eventually the timezone string will be removed and only the struct will be sent.
+    {
       const auto &pt = value.parsed_timezone;
-      time::ParsedTimezone tz{};
-      tz.std_offset_seconds = pt.std_offset_seconds;
-      tz.dst_offset_seconds = pt.dst_offset_seconds;
-      tz.dst_start.time_seconds = pt.dst_start.time_seconds;
-      tz.dst_start.day = static_cast<uint16_t>(pt.dst_start.day);
-      tz.dst_start.type = static_cast<time::DSTRuleType>(pt.dst_start.type);
-      tz.dst_start.month = static_cast<uint8_t>(pt.dst_start.month);
-      tz.dst_start.week = static_cast<uint8_t>(pt.dst_start.week);
-      tz.dst_start.day_of_week = static_cast<uint8_t>(pt.dst_start.day_of_week);
-      tz.dst_end.time_seconds = pt.dst_end.time_seconds;
-      tz.dst_end.day = static_cast<uint16_t>(pt.dst_end.day);
-      tz.dst_end.type = static_cast<time::DSTRuleType>(pt.dst_end.type);
-      tz.dst_end.month = static_cast<uint8_t>(pt.dst_end.month);
-      tz.dst_end.week = static_cast<uint8_t>(pt.dst_end.week);
-      tz.dst_end.day_of_week = static_cast<uint8_t>(pt.dst_end.day_of_week);
-      time::set_global_tz(tz);
+      if (pt.std_offset_seconds != 0 || pt.dst_start.type != enums::DST_RULE_TYPE_NONE) {
+        time::ParsedTimezone tz{};
+        tz.std_offset_seconds = pt.std_offset_seconds;
+        tz.dst_offset_seconds = pt.dst_offset_seconds;
+        tz.dst_start.time_seconds = pt.dst_start.time_seconds;
+        tz.dst_start.day = static_cast<uint16_t>(pt.dst_start.day);
+        tz.dst_start.type = static_cast<time::DSTRuleType>(pt.dst_start.type);
+        tz.dst_start.month = static_cast<uint8_t>(pt.dst_start.month);
+        tz.dst_start.week = static_cast<uint8_t>(pt.dst_start.week);
+        tz.dst_start.day_of_week = static_cast<uint8_t>(pt.dst_start.day_of_week);
+        tz.dst_end.time_seconds = pt.dst_end.time_seconds;
+        tz.dst_end.day = static_cast<uint16_t>(pt.dst_end.day);
+        tz.dst_end.type = static_cast<time::DSTRuleType>(pt.dst_end.type);
+        tz.dst_end.month = static_cast<uint8_t>(pt.dst_end.month);
+        tz.dst_end.week = static_cast<uint8_t>(pt.dst_end.week);
+        tz.dst_end.day_of_week = static_cast<uint8_t>(pt.dst_end.day_of_week);
+        time::set_global_tz(tz);
+      }
     }
 #endif
   }