diff --git a/esphome/components/api/api_pb2.cpp b/esphome/components/api/api_pb2.cpp
index 3594dabc32..6c5b487212 100644
--- a/esphome/components/api/api_pb2.cpp
+++ b/esphome/components/api/api_pb2.cpp
@@ -1133,11 +1133,12 @@ SubscribeLogsResponse::calc_size_msg(const void *self) {
 bool NoiseEncryptionSetKeyRequest::decode_field(uint32_t tag, const uint8_t *data, proto_varint_value_t scalar) {
   const ProtoFieldValue value(data, scalar);
   switch (PROTO_DECODE_KEY(tag)) {
-    case PROTO_DECODE_CASE(1, 2):
+    case PROTO_DECODE_CASE(1, 2): {
       PROTO_DECODE_GUARD(tag, 1, 2);
       this->key = value.data();
       this->key_len = value.size();
       break;
+    }
     default:
       return false;
   }
@@ -1246,11 +1247,12 @@ bool HomeassistantActionResponse::decode_field(uint32_t tag, const uint8_t *data
       this->error_message = StringRef(reinterpret_cast<const char *>(value.data()), value.size());
       break;
 #ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON
-    case PROTO_DECODE_CASE(4, 2):
+    case PROTO_DECODE_CASE(4, 2): {
       PROTO_DECODE_GUARD(tag, 4, 2);
       this->response_data = value.data();
       this->response_data_len = value.size();
       break;
+    }
 #endif
     default:
       return false;
@@ -1360,11 +1362,12 @@ bool GetTimeResponse::decode_field(uint32_t tag, const uint8_t *data, proto_vari
       PROTO_DECODE_GUARD(tag, 1, 5);
       this->epoch_seconds = value.as_fixed32();
       break;
-    case PROTO_DECODE_CASE(3, 2):
+    case PROTO_DECODE_CASE(3, 2): {
       PROTO_DECODE_GUARD(tag, 3, 2);
       value.decode_to_message(this->parsed_timezone);
       this->has_parsed_timezone = true;
       break;
+    }
     default:
       return false;
   }
@@ -1489,11 +1492,12 @@ bool ExecuteServiceRequest::decode_field(uint32_t tag, const uint8_t *data, prot
       PROTO_DECODE_GUARD(tag, 1, 5);
       this->key = value.as_fixed32();
       break;
-    case PROTO_DECODE_CASE(2, 2):
+    case PROTO_DECODE_CASE(2, 2): {
       PROTO_DECODE_GUARD(tag, 2, 2);
       this->args.emplace_back();
       value.decode_to_message(this->args.back());
       break;
+    }
 #ifdef USE_API_USER_DEFINED_ACTION_RESPONSES
     case PROTO_DECODE_CASE(3, 0):
       PROTO_DECODE_GUARD(tag, 3, 0);
@@ -2873,11 +2877,12 @@ bool BluetoothGATTWriteRequest::decode_field(uint32_t tag, const uint8_t *data,
       PROTO_DECODE_GUARD(tag, 3, 0);
       this->response = value.as_varint() != 0;
       break;
-    case PROTO_DECODE_CASE(4, 2):
+    case PROTO_DECODE_CASE(4, 2): {
       PROTO_DECODE_GUARD(tag, 4, 2);
       this->data = value.data();
       this->data_len = value.size();
       break;
+    }
     default:
       return false;
   }
@@ -2910,11 +2915,12 @@ bool BluetoothGATTWriteDescriptorRequest::decode_field(uint32_t tag, const uint8
       PROTO_DECODE_GUARD(tag, 2, 0);
       this->handle = value.as_varint();
       break;
-    case PROTO_DECODE_CASE(3, 2):
+    case PROTO_DECODE_CASE(3, 2): {
       PROTO_DECODE_GUARD(tag, 3, 2);
       this->data = value.data();
       this->data_len = value.size();
       break;
+    }
     default:
       return false;
   }
@@ -3203,11 +3209,12 @@ bool VoiceAssistantEventResponse::decode_field(uint32_t tag, const uint8_t *data
       PROTO_DECODE_GUARD(tag, 1, 0);
       this->event_type = static_cast<enums::VoiceAssistantEvent>(value.as_varint());
       break;
-    case PROTO_DECODE_CASE(2, 2):
+    case PROTO_DECODE_CASE(2, 2): {
       PROTO_DECODE_GUARD(tag, 2, 2);
       this->data.emplace_back();
       value.decode_to_message(this->data.back());
       break;
+    }
     default:
       return false;
   }
@@ -3216,20 +3223,22 @@ bool VoiceAssistantEventResponse::decode_field(uint32_t tag, const uint8_t *data
 bool VoiceAssistantAudio::decode_field(uint32_t tag, const uint8_t *data, proto_varint_value_t scalar) {
   const ProtoFieldValue value(data, scalar);
   switch (PROTO_DECODE_KEY(tag)) {
-    case PROTO_DECODE_CASE(1, 2):
+    case PROTO_DECODE_CASE(1, 2): {
       PROTO_DECODE_GUARD(tag, 1, 2);
       this->data = value.data();
       this->data_len = value.size();
       break;
+    }
     case PROTO_DECODE_CASE(2, 0):
       PROTO_DECODE_GUARD(tag, 2, 0);
       this->end = value.as_varint() != 0;
       break;
-    case PROTO_DECODE_CASE(3, 2):
+    case PROTO_DECODE_CASE(3, 2): {
       PROTO_DECODE_GUARD(tag, 3, 2);
       this->data2 = value.data();
       this->data2_len = value.size();
       break;
+    }
     default:
       return false;
   }
@@ -3381,11 +3390,12 @@ bool VoiceAssistantExternalWakeWord::decode_field(uint32_t tag, const uint8_t *d
 bool VoiceAssistantConfigurationRequest::decode_field(uint32_t tag, const uint8_t *data, proto_varint_value_t scalar) {
   const ProtoFieldValue value(data, scalar);
   switch (PROTO_DECODE_KEY(tag)) {
-    case PROTO_DECODE_CASE(1, 2):
+    case PROTO_DECODE_CASE(1, 2): {
       PROTO_DECODE_GUARD(tag, 1, 2);
       this->external_wake_words.emplace_back();
       value.decode_to_message(this->external_wake_words.back());
       break;
+    }
     default:
       return false;
   }
@@ -4127,11 +4137,12 @@ bool UpdateCommandRequest::decode_field(uint32_t tag, const uint8_t *data, proto
 bool ZWaveProxyFrame::decode_field(uint32_t tag, const uint8_t *data, proto_varint_value_t scalar) {
   const ProtoFieldValue value(data, scalar);
   switch (PROTO_DECODE_KEY(tag)) {
-    case PROTO_DECODE_CASE(1, 2):
+    case PROTO_DECODE_CASE(1, 2): {
       PROTO_DECODE_GUARD(tag, 1, 2);
       this->data = value.data();
       this->data_len = value.size();
       break;
+    }
     default:
       return false;
   }
@@ -4160,11 +4171,12 @@ bool ZWaveProxyRequest::decode_field(uint32_t tag, const uint8_t *data, proto_va
       PROTO_DECODE_GUARD(tag, 1, 0);
       this->type = static_cast<enums::ZWaveProxyRequestType>(value.as_varint());
       break;
-    case PROTO_DECODE_CASE(2, 2):
+    case PROTO_DECODE_CASE(2, 2): {
       PROTO_DECODE_GUARD(tag, 2, 2);
       this->data = value.data();
       this->data_len = value.size();
       break;
+    }
     default:
       return false;
   }
@@ -4259,12 +4271,13 @@ bool InfraredRFTransmitRawTimingsRequest::decode_field(uint32_t tag, const uint8
       PROTO_DECODE_GUARD(tag, 4, 0);
       this->repeat_count = value.as_varint();
       break;
-    case PROTO_DECODE_CASE(5, 2):
+    case PROTO_DECODE_CASE(5, 2): {
       PROTO_DECODE_GUARD(tag, 5, 2);
       this->timings_data_ = value.data();
       this->timings_length_ = value.size();
       this->timings_count_ = count_packed_varints(value.data(), value.size());
       break;
+    }
     case PROTO_DECODE_CASE(6, 0):
       PROTO_DECODE_GUARD(tag, 6, 0);
       this->modulation = value.as_varint();
@@ -4406,11 +4419,12 @@ bool SerialProxyWriteRequest::decode_field(uint32_t tag, const uint8_t *data, pr
       PROTO_DECODE_GUARD(tag, 1, 0);
       this->instance = value.as_varint();
       break;
-    case PROTO_DECODE_CASE(2, 2):
+    case PROTO_DECODE_CASE(2, 2): {
       PROTO_DECODE_GUARD(tag, 2, 2);
       this->data = value.data();
       this->data_len = value.size();
       break;
+    }
     default:
       return false;
   }
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index b1e6cb8ca8..6f6615fa81 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -233,14 +233,17 @@ class TypeInfo(ABC):
     # targets switch on the full wire tag, the host switches on the field number and guards
     # the wire type. Either way a field that arrives with the wrong wire type falls through
     # to "return false" instead of being read from the wrong ProtoFieldValue member.
-    def decode_case(self, wire_type: WireType, body: str) -> str:
-        """Emit one decode_field() case for a field and the wire type it expects."""
-        return (
-            f"case PROTO_DECODE_CASE({self.number}, {int(wire_type)}):\n"
-            f"  PROTO_DECODE_GUARD(tag, {self.number}, {int(wire_type)});\n"
-            f"  {body}\n"
-            f"  break;"
-        )
+    def decode_case(self, wire_type: WireType, body: str, scoped: bool = False) -> str:
+        """Emit one decode_field() case for a field and the wire type it expects.
+
+        Bodies that declare locals must be scoped so the jump to the next case label
+        does not cross an initialization.
+        """
+        label = f"case PROTO_DECODE_CASE({self.number}, {int(wire_type)}):"
+        guard = f"PROTO_DECODE_GUARD(tag, {self.number}, {int(wire_type)});"
+        if scoped:
+            return f"{label} {{\n" + indent(f"{guard}\n{body}\nbreak;") + "\n}"
+        return f"{label}\n" + indent(f"{guard}\n{body}\nbreak;")
 
     @property
     def decode_varint_content(self) -> str:
@@ -1025,7 +1028,8 @@ class MessageType(TypeInfo):
             return self.decode_case(
                 WireType.LENGTH_DELIMITED,
                 f"value.decode_to_message(this->{self.field_name});\n"
-                f"  this->has_{self.name} = true;",
+                f"this->has_{self.name} = true;",
+                scoped=True,
             )
         return self.decode_case(
             WireType.LENGTH_DELIMITED,
@@ -1229,7 +1233,8 @@ class PointerToBytesBufferType(PointerToBufferTypeBase):
         return self.decode_case(
             WireType.LENGTH_DELIMITED,
             f"this->{self.field_name} = value.data();\n"
-            f"  this->{self.field_name}_len = value.size();",
+            f"this->{self.field_name}_len = value.size();",
+            scoped=True,
         )
 
     def dump(self, name: str) -> str:
@@ -1368,8 +1373,9 @@ class PackedBufferTypeInfo(TypeInfo):
         return self.decode_case(
             WireType.LENGTH_DELIMITED,
             f"this->{self.field_name}_data_ = value.data();\n"
-            f"  this->{self.field_name}_length_ = value.size();\n"
-            f"  this->{self.field_name}_count_ = count_packed_varints(value.data(), value.size());",
+            f"this->{self.field_name}_length_ = value.size();\n"
+            f"this->{self.field_name}_count_ = count_packed_varints(value.data(), value.size());",
+            scoped=True,
         )
 
     @property
@@ -1457,12 +1463,12 @@ class FixedArrayBytesType(TypeInfo):
     @property
     def decode_length_content(self) -> str:
         body = "const std::string &data_str = value.as_string();\n"
-        body += f"  this->{self.field_name}_len = data_str.size();\n"
-        body += f"  if (this->{self.field_name}_len > {self.array_size}) {{\n"
-        body += f"    this->{self.field_name}_len = {self.array_size};\n"
-        body += "  }\n"
-        body += f"  memcpy(this->{self.field_name}, data_str.data(), this->{self.field_name}_len);"
-        return self.decode_case(WireType.LENGTH_DELIMITED, body)
+        body += f"this->{self.field_name}_len = data_str.size();\n"
+        body += f"if (this->{self.field_name}_len > {self.array_size}) {{\n"
+        body += f"  this->{self.field_name}_len = {self.array_size};\n"
+        body += "}\n"
+        body += f"memcpy(this->{self.field_name}, data_str.data(), this->{self.field_name}_len);"
+        return self.decode_case(WireType.LENGTH_DELIMITED, body, scoped=True)
 
     @property
     def encode_content(self) -> str:
@@ -2159,7 +2165,8 @@ class RepeatedTypeInfo(TypeInfo):
             return self.decode_case(
                 WireType.LENGTH_DELIMITED,
                 f"this->{self.field_name}.emplace_back();\n"
-                f"  value.decode_to_message(this->{self.field_name}.back());",
+                f"value.decode_to_message(this->{self.field_name}.back());",
+                scoped=True,
             )
         if content is None:
             return None
diff --git a/tests/unit_tests/components/api/test_api_protobuf_generator.py b/tests/unit_tests/components/api/test_api_protobuf_generator.py
index ae629ff11a..908b791a00 100644
--- a/tests/unit_tests/components/api/test_api_protobuf_generator.py
+++ b/tests/unit_tests/components/api/test_api_protobuf_generator.py
@@ -252,3 +252,14 @@ def test_message_gets_a_single_decode_field_override() -> None:
     assert "const ProtoFieldValue value(data, scalar);" in cpp
     for number, wire_type in ((1, 2), (2, 0), (3, 5)):
         assert f"case PROTO_DECODE_CASE({number}, {wire_type}):" in cpp, cpp
+
+
+def test_multi_statement_decode_cases_are_scoped() -> None:
+    """Bodies with several statements or locals get their own block so no jump crosses an initialization."""
+    bytes_type = descriptor_pb2.FieldDescriptorProto.TYPE_BYTES
+    cases = _decode_cases(bytes_type, 4)
+    assert len(cases) == 1, cases
+    lines = cases[0].splitlines()
+    assert lines[0] == "case PROTO_DECODE_CASE(4, 2): {", cases[0]
+    assert lines[-1] == "}", cases[0]
+    assert "value.data();" in cases[0] and "value.size();" in cases[0]