diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index b479b5596a8..f85f4b443de 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -2910,6 +2910,11 @@ Actual: ${stringify(fullActual)}`);
         }
 
         private verifyDocumentHighlights(expectedRanges: Range[], fileNames: ReadonlyArray<string> = [this.activeFile.fileName]) {
+            expectedRanges = ts.map(expectedRanges, r => {
+                r.fileName = ts.normalizePath(r.fileName);
+                return r;
+            });
+            fileNames = ts.map(fileNames, ts.normalizePath);
             const documentHighlights = this.getDocumentHighlightsAtCurrentPosition(fileNames) || [];
 
             for (const dh of documentHighlights) {
@@ -3219,7 +3224,7 @@ Actual: ${stringify(fullActual)}`);
                 }
             }
             else if (ts.isString(indexOrName)) {
-                let name = indexOrName;
+                let name = ts.normalizePath(indexOrName);
 
                 // names are stored in the compiler with this relative path, this allows people to use goTo.file on just the fileName
                 name = name.indexOf("/") === -1 ? (this.basePath + "/" + name) : name;
diff --git a/src/harness/virtualFileSystem.ts b/src/harness/virtualFileSystem.ts
index 16267a092fc..698f99616ca 100644
--- a/src/harness/virtualFileSystem.ts
+++ b/src/harness/virtualFileSystem.ts
@@ -125,7 +125,7 @@ namespace Utils {
 
         addFile(path: string, content?: Harness.LanguageService.ScriptInfo) {
             const absolutePath = ts.normalizePath(ts.getNormalizedAbsolutePath(path, this.currentDirectory));
-            const fileName = ts.getBaseFileName(path);
+            const fileName = ts.getBaseFileName(absolutePath);
             const directoryPath = ts.getDirectoryPath(absolutePath);
             const directory = this.addDirectory(directoryPath);
             return directory ? directory.addFile(fileName, content) : undefined;
diff --git a/tests/cases/fourslash/documentHighlights_windowsPath.ts b/tests/cases/fourslash/documentHighlights_windowsPath.ts
new file mode 100644
index 00000000000..594f175745b
--- /dev/null
+++ b/tests/cases/fourslash/documentHighlights_windowsPath.ts
@@ -0,0 +1,7 @@
+/// <reference path='fourslash.ts' />
+
+//@Filename: C:\a\b\c.ts
+////var /*1*/[|x|] = 1;
+
+const range = test.ranges()[0];
+verify.documentHighlightsOf(range, [range], { filesToSearch: [range.fileName] });
\ No newline at end of file