diff --git a/news/2 Fixes/5362.md b/news/2 Fixes/5362.md
new file mode 100644
index 000000000000..11c7b02f884f
--- /dev/null
+++ b/news/2 Fixes/5362.md	
@@ -0,0 +1 @@
+Fix localhost path mappings to lowercase the drive letter on Windows.
diff --git a/src/client/debugger/extension/configuration/resolvers/attach.ts b/src/client/debugger/extension/configuration/resolvers/attach.ts
index 0f67c89b6b5a..6e5bd6c5ef1c 100644
--- a/src/client/debugger/extension/configuration/resolvers/attach.ts
+++ b/src/client/debugger/extension/configuration/resolvers/attach.ts
@@ -96,8 +96,14 @@ export class AttachConfigurationResolver extends BaseConfigurationResolver<Attac
         if (workspaceFolder && debugConfiguration.host &&
             debugConfiguration.pathMappings!.length === 0 &&
             ['LOCALHOST', '127.0.0.1', '::1'].indexOf(debugConfiguration.host.toUpperCase()) >= 0) {
+            // If on Windows, lowercase the drive letter for path mappings.
+            let localRoot = workspaceFolder.fsPath;
+            if (this.platformService.isWindows && localRoot.match(/^[A-Z]:/)) {
+                localRoot = `${localRoot[0].toLowerCase()}${localRoot.substr(1)}`;
+            }
+
             debugConfiguration.pathMappings!.push({
-                localRoot: workspaceFolder.fsPath,
+                localRoot,
                 remoteRoot: workspaceFolder.fsPath
             });
         }
diff --git a/src/test/debugger/extension/configuration/resolvers/attach.unit.test.ts b/src/test/debugger/extension/configuration/resolvers/attach.unit.test.ts
index ab69b32fca3c..17850cfa5fd2 100644
--- a/src/test/debugger/extension/configuration/resolvers/attach.unit.test.ts
+++ b/src/test/debugger/extension/configuration/resolvers/attach.unit.test.ts
@@ -168,6 +168,38 @@ getNamesAndValues(OSType).forEach(os => {
                 expect(pathMappings![0].localRoot).to.be.equal(workspaceFolder.uri.fsPath);
                 expect(pathMappings![0].remoteRoot).to.be.equal(workspaceFolder.uri.fsPath);
             });
+
+            test(`Ensure drive letter is lower cased for local path mappings on Windows when host is '${host}'`, async function () {
+                if (os.name !== 'Windows') {
+                    return this.skip();
+                }
+
+                const activeFile = 'xyz.py';
+                const workspaceFolder = createMoqWorkspaceFolder(path.join('C:', 'Debug', 'Python_Path'));
+                setupActiveEditor(activeFile, PYTHON_LANGUAGE);
+                const defaultWorkspace = path.join('usr', 'desktop');
+                setupWorkspaces([defaultWorkspace]);
+
+                const localRoot = `Debug_PythonPath_${new Date().toString()}`;
+                const debugConfig = await debugProvider.resolveDebugConfiguration!(workspaceFolder, { localRoot, host, request: 'attach' } as any as DebugConfiguration);
+                const pathMappings = (debugConfig as AttachRequestArguments).pathMappings;
+                const lowercasedLocalRoot = workspaceFolder.uri.fsPath.charAt(0).toLowerCase() + workspaceFolder.uri.fsPath.substr(1);
+
+                expect(pathMappings![0].localRoot).to.be.equal(lowercasedLocalRoot);
+            });
+            test(`Ensure local path mappings are not modified when not pointing to a local drive when host is '${host}'`, async () => {
+                const activeFile = 'xyz.py';
+                const workspaceFolder = createMoqWorkspaceFolder(path.join('Server', 'Debug', 'Python_Path'));
+                setupActiveEditor(activeFile, PYTHON_LANGUAGE);
+                const defaultWorkspace = path.join('usr', 'desktop');
+                setupWorkspaces([defaultWorkspace]);
+
+                const localRoot = `Debug_PythonPath_${new Date().toString()}`;
+                const debugConfig = await debugProvider.resolveDebugConfiguration!(workspaceFolder, { localRoot, host, request: 'attach' } as any as DebugConfiguration);
+                const pathMappings = (debugConfig as AttachRequestArguments).pathMappings;
+
+                expect(pathMappings![0].localRoot).to.be.equal(workspaceFolder.uri.fsPath);
+            });
         });
         ['192.168.1.123', 'don.debugger.com'].forEach(host => {
             test(`Ensure path mappings are not automatically added when host is '${host}'`, async () => {