diff --git a/esphome/components/ld2420/ld2420.h b/esphome/components/ld2420/ld2420.h
index 02250c5911..358793fe64 100644
--- a/esphome/components/ld2420/ld2420.h
+++ b/esphome/components/ld2420/ld2420.h
@@ -21,7 +21,9 @@
 namespace esphome::ld2420 {
 
 static constexpr uint8_t CALIBRATE_SAMPLES = 64;
-static constexpr uint8_t MAX_LINE_LENGTH = 46;  // Max characters for serial buffer
+// Energy frame is 45 bytes; +1 for null terminator, +4 so that a frame footer always lands
+// inside the buffer during footer-based resynchronization after losing sync.
+static constexpr uint8_t MAX_LINE_LENGTH = 50;
 static constexpr uint8_t TOTAL_GATES = 16;
 
 enum OpMode : uint8_t {