diff --git a/crates/uv-distribution-types/src/prioritized_distribution.rs b/crates/uv-distribution-types/src/prioritized_distribution.rs
index 0d88246ac..c96ad9ade 100644
--- a/crates/uv-distribution-types/src/prioritized_distribution.rs
+++ b/crates/uv-distribution-types/src/prioritized_distribution.rs
@@ -860,7 +860,7 @@ fn implied_platform_markers(filename: &WheelFilename) -> MarkerTree {
                 tag_marker.and(MarkerTree::expression(MarkerExpression::String {
                     key: MarkerValueString::PlatformMachine,
                     operator: MarkerOperator::Equal,
-                    value: arcstr::literal!("arm64"),
+                    value: arcstr::literal!("ARM64"),
                 }));
                 marker.or(tag_marker);
             }
@@ -1051,7 +1051,7 @@ mod tests {
         );
         assert_platform_markers(
             "numpy-2.2.1-cp313-cp313t-win_arm64.whl",
-            "sys_platform == 'win32' and platform_machine == 'arm64'",
+            "sys_platform == 'win32' and platform_machine == 'ARM64'",
         );
         assert_platform_markers(
             "numpy-2.2.1-cp313-cp313t-manylinux_2_17_aarch64.manylinux2014_aarch64.whl",
@@ -1128,6 +1128,10 @@ mod tests {
             "numpy-1.0-cp310-cp310-win32.whl",
             "python_full_version == '3.10.*' and platform_python_implementation == 'CPython' and sys_platform == 'win32' and platform_machine == 'x86'",
         );
+        assert_implied_markers(
+            "pywin32-311-cp314-cp314-win_arm64.whl",
+            "python_full_version == '3.14.*' and platform_python_implementation == 'CPython' and sys_platform == 'win32' and platform_machine == 'ARM64'",
+        );
         assert_implied_markers(
             "numpy-1.0-cp311-cp311-macosx_10_9_x86_64.whl",
             "python_full_version == '3.11.*' and platform_python_implementation == 'CPython' and sys_platform == 'darwin' and platform_machine == 'x86_64'",
diff --git a/crates/uv/tests/it/lock.rs b/crates/uv/tests/it/lock.rs
index 7f59a8f71..a45956619 100644
--- a/crates/uv/tests/it/lock.rs
+++ b/crates/uv/tests/it/lock.rs
@@ -29504,6 +29504,79 @@ fn windows_amd64_required() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn windows_arm64_required() -> Result<()> {
+    let context = TestContext::new("3.12").with_exclude_newer("2025-01-30T00:00:00Z");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "pywin32-prj"
+        version = "0.1.0"
+        requires-python = "~=3.12.0"
+        dependencies = ["pywin32; sys_platform == 'win32'"]
+
+        [tool.uv]
+        required-environments = [
+            "sys_platform == 'win32' and platform_machine == 'ARM64'",
+        ]
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock(), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    "###);
+
+    let lock = context.read("uv.lock");
+
+    insta::with_settings!({
+        filters => context.filters(),
+    }, {
+        assert_snapshot!(
+            lock, @r#"
+        version = 1
+        revision = 3
+        requires-python = "==3.12.*"
+        required-markers = [
+            "platform_machine == 'ARM64' and sys_platform == 'win32'",
+        ]
+
+        [options]
+        exclude-newer = "2025-01-30T00:00:00Z"
+
+        [[package]]
+        name = "pywin32"
+        version = "308"
+        source = { registry = "https://pypi.org/simple" }
+        wheels = [
+            { url = "https://files.pythonhosted.org/packages/00/7c/d00d6bdd96de4344e06c4afbf218bc86b54436a94c01c71a8701f613aa56/pywin32-308-cp312-cp312-win32.whl", hash = "sha256:587f3e19696f4bf96fde9d8a57cec74a57021ad5f204c9e627e15c33ff568897", size = 5939729, upload-time = "2024-10-12T20:42:12.001Z" },
+            { url = "https://files.pythonhosted.org/packages/21/27/0c8811fbc3ca188f93b5354e7c286eb91f80a53afa4e11007ef661afa746/pywin32-308-cp312-cp312-win_amd64.whl", hash = "sha256:00b3e11ef09ede56c6a43c71f2d31857cf7c54b0ab6e78ac659497abd2834f47", size = 6543015, upload-time = "2024-10-12T20:42:14.044Z" },
+            { url = "https://files.pythonhosted.org/packages/9d/0f/d40f8373608caed2255781a3ad9a51d03a594a1248cd632d6a298daca693/pywin32-308-cp312-cp312-win_arm64.whl", hash = "sha256:9b4de86c8d909aed15b7011182c8cab38c8850de36e6afb1f0db22b8959e3091", size = 7976033, upload-time = "2024-10-12T20:42:16.215Z" },
+        ]
+
+        [[package]]
+        name = "pywin32-prj"
+        version = "0.1.0"
+        source = { virtual = "." }
+        dependencies = [
+            { name = "pywin32", marker = "sys_platform == 'win32'" },
+        ]
+
+        [package.metadata]
+        requires-dist = [{ name = "pywin32", marker = "sys_platform == 'win32'" }]
+        "#
+        );
+    });
+
+    Ok(())
+}
+
 #[test]
 fn lock_empty_extra() -> Result<()> {
     let context = TestContext::new("3.12");