diff --git a/ChangeLog.md b/ChangeLog.md
index 700d5e8f..4bdbf53d 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -20,6 +20,11 @@ used.  Thus, this issue did not cause a segfault or other user-visible errant
 behavior (it was only detectable with ASan), and it did not likely pose a
 security risk.
 
+4. The AArch64 (Arm 64-bit) Neon SIMD extensions and accelerated Huffman codec
+now support the Arm64EC ABI on Windows, which allows Windows/x64 applications
+to call native Arm64 functions when running under the Windows/x64 emulator on
+Windows/Arm.
+
 
 3.1.1
 =====
diff --git a/simd/arm/jccolor-neon.c b/simd/arm/jccolor-neon.c
index d14a7bf5..8e40bc1e 100644
--- a/simd/arm/jccolor-neon.c
+++ b/simd/arm/jccolor-neon.c
@@ -2,7 +2,7 @@
  * jccolor-neon.c - colorspace conversion (Arm Neon)
  *
  * Copyright (C) 2020, Arm Limited.  All Rights Reserved.
- * Copyright (C) 2020, 2024, D. R. Commander.  All Rights Reserved.
+ * Copyright (C) 2020, 2024-2025, D. R. Commander.  All Rights Reserved.
  *
  * This software is provided 'as-is', without any express or implied
  * warranty.  In no event will the authors be held liable for any damages
@@ -53,7 +53,7 @@ ALIGN(16) static const uint16_t jsimd_rgb_ycc_neon_consts[] = {
 
 /* Include inline routines for colorspace extensions. */
 
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #include "aarch64/jccolext-neon.c"
 #else
 #include "aarch32/jccolext-neon.c"
@@ -68,7 +68,7 @@ ALIGN(16) static const uint16_t jsimd_rgb_ycc_neon_consts[] = {
 #define RGB_BLUE  EXT_RGB_BLUE
 #define RGB_PIXELSIZE  EXT_RGB_PIXELSIZE
 #define jsimd_rgb_ycc_convert_neon  jsimd_extrgb_ycc_convert_neon
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #include "aarch64/jccolext-neon.c"
 #else
 #include "aarch32/jccolext-neon.c"
@@ -84,7 +84,7 @@ ALIGN(16) static const uint16_t jsimd_rgb_ycc_neon_consts[] = {
 #define RGB_BLUE  EXT_RGBX_BLUE
 #define RGB_PIXELSIZE  EXT_RGBX_PIXELSIZE
 #define jsimd_rgb_ycc_convert_neon  jsimd_extrgbx_ycc_convert_neon
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #include "aarch64/jccolext-neon.c"
 #else
 #include "aarch32/jccolext-neon.c"
@@ -100,7 +100,7 @@ ALIGN(16) static const uint16_t jsimd_rgb_ycc_neon_consts[] = {
 #define RGB_BLUE  EXT_BGR_BLUE
 #define RGB_PIXELSIZE  EXT_BGR_PIXELSIZE
 #define jsimd_rgb_ycc_convert_neon  jsimd_extbgr_ycc_convert_neon
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #include "aarch64/jccolext-neon.c"
 #else
 #include "aarch32/jccolext-neon.c"
@@ -116,7 +116,7 @@ ALIGN(16) static const uint16_t jsimd_rgb_ycc_neon_consts[] = {
 #define RGB_BLUE  EXT_BGRX_BLUE
 #define RGB_PIXELSIZE  EXT_BGRX_PIXELSIZE
 #define jsimd_rgb_ycc_convert_neon  jsimd_extbgrx_ycc_convert_neon
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #include "aarch64/jccolext-neon.c"
 #else
 #include "aarch32/jccolext-neon.c"
@@ -132,7 +132,7 @@ ALIGN(16) static const uint16_t jsimd_rgb_ycc_neon_consts[] = {
 #define RGB_BLUE  EXT_XBGR_BLUE
 #define RGB_PIXELSIZE  EXT_XBGR_PIXELSIZE
 #define jsimd_rgb_ycc_convert_neon  jsimd_extxbgr_ycc_convert_neon
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #include "aarch64/jccolext-neon.c"
 #else
 #include "aarch32/jccolext-neon.c"
@@ -148,7 +148,7 @@ ALIGN(16) static const uint16_t jsimd_rgb_ycc_neon_consts[] = {
 #define RGB_BLUE  EXT_XRGB_BLUE
 #define RGB_PIXELSIZE  EXT_XRGB_PIXELSIZE
 #define jsimd_rgb_ycc_convert_neon  jsimd_extxrgb_ycc_convert_neon
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #include "aarch64/jccolext-neon.c"
 #else
 #include "aarch32/jccolext-neon.c"
diff --git a/simd/arm/jchuff.h b/simd/arm/jchuff.h
index 2fbd252b..5ca96293 100644
--- a/simd/arm/jchuff.h
+++ b/simd/arm/jchuff.h
@@ -4,7 +4,7 @@
  * This file was part of the Independent JPEG Group's software:
  * Copyright (C) 1991-1997, Thomas G. Lane.
  * libjpeg-turbo Modifications:
- * Copyright (C) 2009, 2018, 2021, D. R. Commander.
+ * Copyright (C) 2009, 2018, 2021, 2025, D. R. Commander.
  * Copyright (C) 2018, Matthias Räncker.
  * Copyright (C) 2020-2021, Arm Limited.
  * For conditions of distribution and use, see the accompanying README.ijg
@@ -17,7 +17,7 @@
  * but must not be updated permanently until we complete the MCU.
  */
 
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #define BIT_BUF_SIZE  64
 #else
 #define BIT_BUF_SIZE  32
@@ -54,7 +54,7 @@ typedef struct {
  * directly to the output buffer.  Otherwise, use the EMIT_BYTE() macro to
  * encode 0xFF as 0xFF 0x00.
  */
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
 
 #define FLUSH() { \
   if (put_buffer & 0x8080808080808080 & ~(put_buffer + 0x0101010101010101)) { \
diff --git a/simd/arm/jcphuff-neon.c b/simd/arm/jcphuff-neon.c
index 435f96ee..cfc4d914 100644
--- a/simd/arm/jcphuff-neon.c
+++ b/simd/arm/jcphuff-neon.c
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2020-2021, Arm Limited.  All Rights Reserved.
  * Copyright (C) 2022, Matthieu Darbois.  All Rights Reserved.
- * Copyright (C) 2022, 2024, D. R. Commander.  All Rights Reserved.
+ * Copyright (C) 2022, 2024-2025, D. R. Commander.  All Rights Reserved.
  *
  * This software is provided 'as-is', without any express or implied
  * warranty.  In no event will the authors be held liable for any damages
@@ -251,7 +251,7 @@ void jsimd_encode_mcu_AC_first_prepare_neon
   uint8x8_t bitmap_rows_4567 = vpadd_u8(bitmap_rows_45, bitmap_rows_67);
   uint8x8_t bitmap_all = vpadd_u8(bitmap_rows_0123, bitmap_rows_4567);
 
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
   /* Move bitmap to a 64-bit scalar register. */
   uint64_t bitmap = vget_lane_u64(vreinterpret_u64_u8(bitmap_all), 0);
   /* Store zerobits bitmap. */
@@ -511,7 +511,7 @@ int jsimd_encode_mcu_AC_refine_prepare_neon
   uint8x8_t bitmap_rows_4567 = vpadd_u8(bitmap_rows_45, bitmap_rows_67);
   uint8x8_t bitmap_all = vpadd_u8(bitmap_rows_0123, bitmap_rows_4567);
 
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
   /* Move bitmap to a 64-bit scalar register. */
   uint64_t bitmap = vget_lane_u64(vreinterpret_u64_u8(bitmap_all), 0);
   /* Store zerobits bitmap. */
@@ -552,7 +552,7 @@ int jsimd_encode_mcu_AC_refine_prepare_neon
   bitmap_rows_4567 = vpadd_u8(bitmap_rows_45, bitmap_rows_67);
   bitmap_all = vpadd_u8(bitmap_rows_0123, bitmap_rows_4567);
 
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
   /* Move bitmap to a 64-bit scalar register. */
   bitmap = vget_lane_u64(vreinterpret_u64_u8(bitmap_all), 0);
   /* Store signbits bitmap. */
@@ -595,7 +595,7 @@ int jsimd_encode_mcu_AC_refine_prepare_neon
   bitmap_rows_4567 = vpadd_u8(bitmap_rows_45, bitmap_rows_67);
   bitmap_all = vpadd_u8(bitmap_rows_0123, bitmap_rows_4567);
 
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
   /* Move bitmap to a 64-bit scalar register. */
   bitmap = vget_lane_u64(vreinterpret_u64_u8(bitmap_all), 0);
 
diff --git a/simd/arm/jcsample-neon.c b/simd/arm/jcsample-neon.c
index fd8a93e5..9ad1acf5 100644
--- a/simd/arm/jcsample-neon.c
+++ b/simd/arm/jcsample-neon.c
@@ -2,7 +2,7 @@
  * jcsample-neon.c - downsampling (Arm Neon)
  *
  * Copyright (C) 2020, Arm Limited.  All Rights Reserved.
- * Copyright (C) 2024, D. R. Commander.  All Rights Reserved.
+ * Copyright (C) 2024-2025, D. R. Commander.  All Rights Reserved.
  *
  * This software is provided 'as-is', without any express or implied
  * warranty.  In no event will the authors be held liable for any damages
@@ -107,7 +107,7 @@ void jsimd_h2v1_downsample_neon(JDIMENSION image_width, int max_v_samp_factor,
 
     /* Load pixels in last DCT block into a table. */
     uint8x16_t pixels = vld1q_u8(inptr + (width_in_blocks - 1) * 2 * DCTSIZE);
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
     /* Pad the empty elements with the value of the last pixel. */
     pixels = vqtbl1q_u8(pixels, expand_mask);
 #else
@@ -169,7 +169,7 @@ void jsimd_h2v2_downsample_neon(JDIMENSION image_width, int max_v_samp_factor,
       vld1q_u8(inptr0 + (width_in_blocks - 1) * 2 * DCTSIZE);
     uint8x16_t pixels_r1 =
       vld1q_u8(inptr1 + (width_in_blocks - 1) * 2 * DCTSIZE);
-#if defined(__aarch64__) || defined(_M_ARM64)
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
     /* Pad the empty elements with the value of the last pixel. */
     pixels_r0 = vqtbl1q_u8(pixels_r0, expand_mask);
     pixels_r1 = vqtbl1q_u8(pixels_r1, expand_mask);
diff --git a/simd/arm/jquanti-neon.c b/simd/arm/jquanti-neon.c
index e44fb3d4..48594d77 100644
--- a/simd/arm/jquanti-neon.c
+++ b/simd/arm/jquanti-neon.c
@@ -2,7 +2,7 @@
  * jquanti-neon.c - sample data conversion and quantization (Arm Neon)
  *
  * Copyright (C) 2020-2021, Arm Limited.  All Rights Reserved.
- * Copyright (C) 2024, D. R. Commander.  All Rights Reserved.
+ * Copyright (C) 2024-2025, D. R. Commander.  All Rights Reserved.
  *
  * This software is provided 'as-is', without any express or implied
  * warranty.  In no event will the authors be held liable for any damages
@@ -102,7 +102,8 @@ void jsimd_quantize_neon(JCOEFPTR coef_block, DCTELEM *divisors,
   DCTELEM *shift_ptr = divisors + 3 * DCTSIZE2;
   int i;
 
-#if defined(__clang__) && (defined(__aarch64__) || defined(_M_ARM64))
+#if defined(__clang__) && (defined(__aarch64__) || defined(_M_ARM64) || \
+                           defined(_M_ARM64EC))
 #pragma unroll
 #endif
   for (i = 0; i < DCTSIZE; i += DCTSIZE / 2) {
diff --git a/src/jchuff.c b/src/jchuff.c
index 8cdd5bd3..781e1ca7 100644
--- a/src/jchuff.c
+++ b/src/jchuff.c
@@ -6,7 +6,7 @@
  * Lossless JPEG Modifications:
  * Copyright (C) 1999, Ken Murchison.
  * libjpeg-turbo Modifications:
- * Copyright (C) 2009-2011, 2014-2016, 2018-2024, D. R. Commander.
+ * Copyright (C) 2009-2011, 2014-2016, 2018-2025, D. R. Commander.
  * Copyright (C) 2015, Matthieu Darbois.
  * Copyright (C) 2018, Matthias Räncker.
  * Copyright (C) 2020, Arm Limited.
@@ -55,7 +55,8 @@ typedef size_t bit_buf_type;
  * retain the old Huffman encoder behavior when using the GAS implementation.
  */
 #if defined(WITH_SIMD) && !(defined(__arm__) || defined(__aarch64__) || \
-                            defined(_M_ARM) || defined(_M_ARM64))
+                            defined(_M_ARM) || defined(_M_ARM64) || \
+                            defined(_M_ARM64EC))
 typedef unsigned long long simd_bit_buf_type;
 #else
 typedef bit_buf_type simd_bit_buf_type;
diff --git a/src/jdsample.c b/src/jdsample.c
index e5a127de..022471dc 100644
--- a/src/jdsample.c
+++ b/src/jdsample.c
@@ -5,7 +5,7 @@
  * Copyright (C) 1991-1996, Thomas G. Lane.
  * libjpeg-turbo Modifications:
  * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
- * Copyright (C) 2010, 2015-2016, 2022, 2024, D. R. Commander.
+ * Copyright (C) 2010, 2015-2016, 2022, 2024-2025, D. R. Commander.
  * Copyright (C) 2014, MIPS Technologies, Inc., California.
  * Copyright (C) 2015, Google, Inc.
  * Copyright (C) 2019-2020, Arm Limited.
@@ -501,7 +501,8 @@ _jinit_upsampler(j_decompress_ptr cinfo)
                v_in_group * 2 == v_out_group && do_fancy) {
       /* Non-fancy upsampling is handled by the generic method */
 #if defined(WITH_SIMD) && (defined(__arm__) || defined(__aarch64__) || \
-                           defined(_M_ARM) || defined(_M_ARM64))
+                           defined(_M_ARM) || defined(_M_ARM64) || \
+                           defined(_M_ARM64EC))
       if (jsimd_can_h1v2_fancy_upsample())
         upsample->methods[ci] = jsimd_h1v2_fancy_upsample;
       else
diff --git a/src/jpeg_nbits.c b/src/jpeg_nbits.c
index c8ee6b05..752a1636 100644
--- a/src/jpeg_nbits.c
+++ b/src/jpeg_nbits.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2024, D. R. Commander.
+ * Copyright (C) 2024-2025, D. R. Commander.
  *
  * For conditions of distribution and use, see the accompanying README.ijg
  * file.
@@ -17,7 +17,7 @@
  * encoders can reuse jpeg_nbits_table from the SSE2 baseline Huffman encoder.
  */
 #if (defined(__x86_64__) || defined(__i386__) || defined(_M_IX86) || \
-     defined(_M_X64)) && defined(WITH_SIMD)
+     (defined(_M_X64) && !defined(_M_ARM64EC))) && defined(WITH_SIMD)
 #undef INCLUDE_JPEG_NBITS_TABLE
 #endif
 
diff --git a/src/jpeg_nbits.h b/src/jpeg_nbits.h
index 6481a122..61666fd5 100644
--- a/src/jpeg_nbits.h
+++ b/src/jpeg_nbits.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014, 2021, 2024, D. R. Commander.
+ * Copyright (C) 2014, 2021, 2024-2025, D. R. Commander.
  * Copyright (C) 2014, Olle Liljenzin.
  * Copyright (C) 2020, Arm Limited.
  *
@@ -23,7 +23,7 @@
 
 /* NOTE: Both GCC and Clang define __GNUC__ */
 #if (defined(__GNUC__) && (defined(__arm__) || defined(__aarch64__))) || \
-    defined(_M_ARM) || defined(_M_ARM64)
+    defined(_M_ARM) || defined(_M_ARM64) || defined(_M_ARM64EC)
 #if !defined(__thumb__) || defined(__thumb2__)
 #define USE_CLZ_INTRINSIC
 #endif