diff --git a/esphome/components/sha256/sha256.cpp b/esphome/components/sha256/sha256.cpp
index 32abbd739d..48559d7c73 100644
--- a/esphome/components/sha256/sha256.cpp
+++ b/esphome/components/sha256/sha256.cpp
@@ -10,23 +10,26 @@ namespace esphome::sha256 {
 
 #if defined(USE_ESP32) || defined(USE_LIBRETINY)
 
-// CRITICAL ESP32-S3 HARDWARE SHA ACCELERATION REQUIREMENTS:
+// CRITICAL ESP32-S3 HARDWARE SHA ACCELERATION REQUIREMENTS (IDF 5.5.x):
 //
 // The ESP32-S3 uses hardware DMA for SHA acceleration. The mbedtls_sha256_context structure contains
-// internal state that the DMA engine references. This imposes two critical constraints:
+// internal state that the DMA engine references. This imposes three critical constraints:
 //
-// 1. NO VARIABLE LENGTH ARRAYS (VLAs): VLAs corrupt the stack layout, causing the DMA engine to
+// 1. ALIGNMENT: The SHA256 object MUST be declared with `alignas(32)` for proper DMA alignment.
+//    Without this, the DMA engine may crash with an abort in sha_hal_read_digest().
+//
+// 2. NO VARIABLE LENGTH ARRAYS (VLAs): VLAs corrupt the stack layout, causing the DMA engine to
 //    write to incorrect memory locations. This results in null pointer dereferences and crashes.
 //    ALWAYS use fixed-size arrays (e.g., char buf[65], not char buf[size+1]).
 //
-// 2. SAME STACK FRAME ONLY: The SHA256 object must be created and used entirely within the same
+// 3. SAME STACK FRAME ONLY: The SHA256 object must be created and used entirely within the same
 //    function. NEVER pass the SHA256 object or HashBase pointer to another function. When the stack
 //    frame changes (function call/return), the DMA references become invalid and will produce
 //    truncated hash output (20 bytes instead of 32) or corrupt memory.
 //
 // CORRECT USAGE:
 //   void my_function() {
-//     sha256::SHA256 hasher;  // Created locally
+//     alignas(32) sha256::SHA256 hasher;  // Created locally with proper alignment
 //     hasher.init();
 //     hasher.add(data, len);  // Any size, no chunking needed
 //     hasher.calculate();
@@ -36,7 +39,7 @@ namespace esphome::sha256 {
 //
 // INCORRECT USAGE (WILL FAIL ON ESP32-S3):
 //   void my_function() {
-//     sha256::SHA256 hasher;
+//     sha256::SHA256 hasher;  // WRONG: Missing alignas(32)
 //     helper(&hasher);  // WRONG: Passed to different stack frame
 //   }
 //   void helper(HashBase *h) {