diff --git a/packages/nx/src/project-graph/utils/find-project-for-path.ts b/packages/nx/src/project-graph/utils/find-project-for-path.ts
index 8ef705cc67e1b..6522b7be64f1c 100644
--- a/packages/nx/src/project-graph/utils/find-project-for-path.ts
+++ b/packages/nx/src/project-graph/utils/find-project-for-path.ts
@@ -1,6 +1,7 @@
 import { dirname } from 'path';
 import { ProjectGraphProjectNode } from '../../config/project-graph';
 import { ProjectConfiguration } from '../../config/workspace-json-project-json';
+import { normalizePath } from '../../utils/path';
 
 export type ProjectRootMappings = Map<string, string>;
 
@@ -44,7 +45,12 @@ export function findProjectForPath(
   filePath: string,
   projectRootMap: ProjectRootMappings
 ): string | null {
-  let currentPath = filePath;
+  /**
+   * Project Mappings are in UNIX-style file paths
+   * Windows may pass Win-style file paths
+   * Ensure filePath is in UNIX-style
+   */
+  let currentPath = normalizePath(filePath);
   for (
     ;
     currentPath != dirname(currentPath);