diff --git a/packages/gatsby-source-filesystem/package.json b/packages/gatsby-source-filesystem/package.json
index be9b36223a1d5..b37d7a5f06d4f 100644
--- a/packages/gatsby-source-filesystem/package.json
+++ b/packages/gatsby-source-filesystem/package.json
@@ -19,7 +19,6 @@
     "pretty-bytes": "^4.0.2",
     "progress": "^1.1.8",
     "read-chunk": "^3.0.0",
-    "slash": "^1.0.0",
     "valid-url": "^1.0.9",
     "xstate": "^3.1.0"
   },
diff --git a/packages/gatsby-source-filesystem/src/__tests__/utils.js b/packages/gatsby-source-filesystem/src/__tests__/utils.js
index 9a8ac914f991a..298a7fe8f982a 100644
--- a/packages/gatsby-source-filesystem/src/__tests__/utils.js
+++ b/packages/gatsby-source-filesystem/src/__tests__/utils.js
@@ -1,4 +1,4 @@
-const { getRemoteFileExtension, getRemoteFileName } = require(`../utils`)
+const { getRemoteFileExtension, getRemoteFileName, slash } = require(`../utils`)
 
 describe(`create remote file node`, () => {
   it(`can correctly retrieve file name and extensions`, () => {
@@ -22,3 +22,20 @@ describe(`create remote file node`, () => {
     })
   })
 })
+
+describe(`slash path`, () => {
+  it(`can correctly slash path`, () => {
+    ;[
+      [`foo\\bar`, `foo/bar`],
+      [`foo/bar`, `foo/bar`],
+      [`foo\\中文`, `foo/中文`],
+      [`foo/中文`, `foo/中文`],
+    ].forEach(([path, expectRes]) => {
+      expect(slash(path)).toBe(expectRes)
+    })
+  })
+  it(`does not modify extended length paths`, () => {
+    const extended = `\\\\?\\some\\path`
+    expect(slash(extended)).toBe(extended)
+  })
+})
diff --git a/packages/gatsby-source-filesystem/src/create-file-node.js b/packages/gatsby-source-filesystem/src/create-file-node.js
index 2a39890979732..bb9e9ed74a7d6 100644
--- a/packages/gatsby-source-filesystem/src/create-file-node.js
+++ b/packages/gatsby-source-filesystem/src/create-file-node.js
@@ -1,4 +1,4 @@
-const slash = require(`slash`)
+const { slash } = require(`./utils`)
 const path = require(`path`)
 const fs = require(`fs-extra`)
 const mime = require(`mime`)
diff --git a/packages/gatsby-source-filesystem/src/create-file-path.js b/packages/gatsby-source-filesystem/src/create-file-path.js
index fe930d908fa4d..2d72d3a8e9682 100644
--- a/packages/gatsby-source-filesystem/src/create-file-path.js
+++ b/packages/gatsby-source-filesystem/src/create-file-path.js
@@ -1,5 +1,5 @@
 const path = require(`path`)
-const slash = require(`slash`)
+const { slash } = require(`./utils`)
 
 function findFileNode({ node, getNode }) {
   // Find the file node.
diff --git a/packages/gatsby-source-filesystem/src/utils.js b/packages/gatsby-source-filesystem/src/utils.js
index 7d2e4032c7be7..24e03f31e525d 100644
--- a/packages/gatsby-source-filesystem/src/utils.js
+++ b/packages/gatsby-source-filesystem/src/utils.js
@@ -39,3 +39,22 @@ export function getRemoteFileExtension(url) {
 export function getRemoteFileName(url) {
   return getParsedPath(url).name
 }
+
+/**
+ * slash
+ * --
+ * Convert Windows backslash paths to slash paths: foo\\bar ➔ foo/bar
+ *
+ *
+ * @param  {String}          path
+ * @return {String}          slashed path
+ */
+export function slash(path) {
+  const isExtendedLengthPath = /^\\\\\?\\/.test(path)
+
+  if (isExtendedLengthPath) {
+    return path
+  }
+
+  return path.replace(/\\/g, `/`)
+}