diff --git a/package-lock.json b/package-lock.json
index f22f147e..cb6f488c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8103,8 +8103,7 @@
     "normalize-path": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/normalize-path/-/normalize-path-3.0.0.tgz",
-      "integrity": "sha512-6eZs5Ls3WtCisHWp9S2GUy8dqkpGi4BVSz3GaqiE6ezub0512ESztXUwUB6C6IKbQkY2Pnb/mD4WYojCRwcwLA==",
-      "dev": true
+      "integrity": "sha512-6eZs5Ls3WtCisHWp9S2GUy8dqkpGi4BVSz3GaqiE6ezub0512ESztXUwUB6C6IKbQkY2Pnb/mD4WYojCRwcwLA=="
     },
     "npm-path": {
       "version": "2.0.4",
diff --git a/package.json b/package.json
index 543d986f..6adfacf1 100644
--- a/package.json
+++ b/package.json
@@ -40,14 +40,15 @@
     "webpack": "^4.0.0"
   },
   "dependencies": {
-    "globby": "^7.1.1",
     "cacache": "^11.3.1",
     "find-cache-dir": "^2.0.0",
-    "serialize-javascript": "^1.4.0",
+    "globby": "^7.1.1",
     "is-glob": "^4.0.0",
     "loader-utils": "^1.1.0",
     "minimatch": "^3.0.4",
-    "p-limit": "^2.1.0"
+    "normalize-path": "^3.0.0",
+    "p-limit": "^2.1.0",
+    "serialize-javascript": "^1.4.0"
   },
   "devDependencies": {
     "@babel/cli": "^7.1.5",
diff --git a/src/preProcessPattern.js b/src/preProcessPattern.js
index 234249e1..3dc14c8f 100644
--- a/src/preProcessPattern.js
+++ b/src/preProcessPattern.js
@@ -1,6 +1,7 @@
 import path from 'path';
 
 import isGlob from 'is-glob';
+import normalizePath from 'normalize-path';
 
 import escape from './utils/escape';
 import isObject from './utils/isObject';
@@ -30,6 +31,18 @@ export default function preProcessPattern(globalRef, pattern) {
         }
       : Object.assign({}, pattern);
 
+  if (typeof pattern.from === 'string') {
+    pattern.from = normalizePath(pattern.from);
+  } else if (
+    typeof pattern.from === 'object' &&
+    typeof pattern.from.glob === 'string'
+  ) {
+    pattern.from = {
+      ...pattern.from,
+      glob: normalizePath(pattern.from.glob),
+    };
+  }
+
   if (pattern.from === '') {
     throw new Error('[copy-webpack-plugin] path "from" cannot be empty string');
   }
diff --git a/test/CopyPlugin.test.js b/test/CopyPlugin.test.js
index b326bc3f..c98c60fb 100644
--- a/test/CopyPlugin.test.js
+++ b/test/CopyPlugin.test.js
@@ -298,6 +298,19 @@ describe('apply function', () => {
         .catch(done);
     });
 
+    it('can normalize backslash path', (done) => {
+      runEmit({
+        expectedAssetKeys: ['directory/nested/nestedfile.txt'],
+        patterns: [
+          {
+            from: 'directory\\nested\\*',
+          },
+        ],
+      })
+        .then(done)
+        .catch(done);
+    });
+
     it('can use a bracketed glob to move a file to the root directory', (done) => {
       runEmit({
         expectedAssetKeys: [