diff --git a/overlays/ports/libass/arm64-windows-asm.patch b/overlays/ports/libass/arm64-windows-asm.patch
new file mode 100644
index 0000000..8828f8d
--- /dev/null
+++ b/overlays/ports/libass/arm64-windows-asm.patch
@@ -0,0 +1,59 @@
+diff --git a/libass/meson.build b/libass/meson.build
+index 5251c2f..a3429bb 100644
+--- a/libass/meson.build
++++ b/libass/meson.build
+@@ -70,6 +70,28 @@ if enable_asm
+ 
+     if asm_is_nasm
+         libass_src += asm_sources
++    elif asm_is_clang
++        clang = find_program('clang')
++        foreach asm_source : asm_sources
++            asm_output = fs.stem(asm_source.full_path()) + '.obj'
++            libass_src += custom_target(
++                asm_output,
++                input: asm_source,
++                output: asm_output,
++                depends: config_h,
++                command: [
++                    clang,
++                ] + asm_clang_args + [
++                    '-I' + meson.project_build_root(),
++                    '-I' + meson.current_source_dir(),
++                ] + asm_args + [
++                    '-c',
++                    '@INPUT@',
++                    '-o',
++                    '@OUTPUT@',
++                ],
++            )
++        endforeach
+     else
+         asm_lib = static_library(
+             'libass_asm',
+diff --git a/meson.build b/meson.build
+index 4b1c24e..b82233e 100644
+--- a/meson.build
++++ b/meson.build
+@@ -207,7 +207,9 @@ endif
+ enable_asm = false
+ # used in libass/meson.build
+ asm_is_nasm = false
++asm_is_clang = false
+ asm_args = []
++asm_clang_args = []
+ 
+ # ASM architecture variables
+ asm_option = get_option('asm')
+@@ -276,6 +278,10 @@ if not asm_option.disabled()
+         enable_asm = true
+         conf.set('ARCH_AARCH64', 1)
+         if host_system == 'darwin'
+             asm_args += '-DPREFIX'
++        elif host_system == 'windows' and cc.get_argument_syntax() == 'msvc' and cc.get_id() != 'clang-cl'
++            # MSVC cannot compile GNU-style AArch64 .S sources.
++            asm_is_clang = true
++            asm_clang_args += '--target=arm64-pc-windows-msvc'
+         endif
+     else
+         warning(
diff --git a/overlays/ports/libass/portfile.cmake b/overlays/ports/libass/portfile.cmake
new file mode 100644
index 0000000..4ac9259
--- /dev/null
+++ b/overlays/ports/libass/portfile.cmake
@@ -0,0 +1,61 @@
+vcpkg_from_github(
+    OUT_SOURCE_PATH SOURCE_PATH
+    REPO libass/libass
+    REF ${VERSION}
+    SHA512 08762623dd09e3034699ba9d11b70d1f6cc6b2e3b38aa897b07efef1364e76141df484e70ed27888cf3595b77d072cdb5e8abbbfa560e33ca21f87872e24df8d
+    HEAD_REF master
+    PATCHES
+        arm64-windows-asm.patch
+)
+
+vcpkg_find_acquire_program(PKGCONFIG)
+get_filename_component(PKGCONFIG_EXE_PATH "${PKGCONFIG}" DIRECTORY)
+vcpkg_add_to_path("${PKGCONFIG_EXE_PATH}")
+
+list(APPEND options
+    -Dcheckasm=disabled
+    -Dcompare=disabled
+    -Dfuzz=disabled
+    -Dprofile=disabled
+    -Dtest=disabled
+)
+
+if(NOT VCPKG_TARGET_IS_WINDOWS AND NOT VCPKG_TARGET_IS_OSX AND NOT VCPKG_TARGET_IS_LINUX)
+    # On non-desktop targets (e.g. Android, iOS, Emscripten) there is no
+    # system font provider and fontconfig headers are not available, so
+    # disable both the system-font-provider requirement and the fontconfig
+    # integration to prevent meson from compiling ass_fontconfig.c.
+    list(APPEND options -Drequire-system-font-provider=false -Dfontconfig=disabled)
+endif()
+
+set(asm_option disabled)
+set(additional_binaries "")
+if(VCPKG_TARGET_ARCHITECTURE MATCHES "^(x86|x64|arm64)$")
+    set(asm_option enabled)
+    if(VCPKG_TARGET_ARCHITECTURE MATCHES "^(x86|x64)$")
+        vcpkg_find_acquire_program(NASM)
+        get_filename_component(NASM_EXE_PATH "${NASM}" DIRECTORY)
+        vcpkg_add_to_path("${NASM_EXE_PATH}")
+    elseif(VCPKG_TARGET_IS_WINDOWS AND VCPKG_TARGET_ARCHITECTURE STREQUAL "arm64")
+        vcpkg_find_acquire_program(CLANG)
+        list(APPEND additional_binaries "clang = ['${CLANG}']")
+    endif()
+else()
+    message(WARNING "Assembly optimizations are not supported on ${VCPKG_TARGET_ARCHITECTURE}; disabling assembly optimizations.")
+endif()
+list(APPEND options -Dasm=${asm_option})
+
+vcpkg_configure_meson(
+    SOURCE_PATH "${SOURCE_PATH}"
+    OPTIONS
+        ${options}
+    ADDITIONAL_BINARIES
+        ${additional_binaries}
+)
+
+vcpkg_install_meson()
+vcpkg_copy_pdbs()
+vcpkg_fixup_pkgconfig()
+
+# Handle copyright
+vcpkg_install_copyright(FILE_LIST "${SOURCE_PATH}/COPYING")
diff --git a/overlays/ports/libass/vcpkg.json b/overlays/ports/libass/vcpkg.json
new file mode 100644
index 0000000..8ffa242
--- /dev/null
+++ b/overlays/ports/libass/vcpkg.json
@@ -0,0 +1,21 @@
+{
+  "name": "libass",
+  "version": "0.17.4",
+  "port-version": 1,
+  "description": "libass is a portable subtitle renderer for the ASS/SSA (Advanced Substation Alpha/Substation Alpha) subtitle format",
+  "homepage": "https://github.com/libass/libass",
+  "license": "ISC",
+  "dependencies": [
+    {
+      "name": "fontconfig",
+      "platform": "linux | osx"
+    },
+    "freetype",
+    "fribidi",
+    "harfbuzz",
+    {
+      "name": "vcpkg-tool-meson",
+      "host": true
+    }
+  ]
+}