diff --git a/.eslintrc.js b/.eslintrc.js
index 3d77b69..0eaca9f 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -6,7 +6,7 @@ module.exports = {
   },
   extends: ["eslint:recommended", "prettier"],
   parserOptions: {
-    ecmaVersion: 2017
+    ecmaVersion: 2018
   },
   plugins: ["jest"],
   rules: {
diff --git a/.gitignore b/.gitignore
index debc521..cd76a6f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 node_modules/
 coverage/
 .vscode
+.idea/
diff --git a/__tests__/fileSet.test.js b/__tests__/fileSet.test.js
index 6b22f22..2720df1 100644
--- a/__tests__/fileSet.test.js
+++ b/__tests__/fileSet.test.js
@@ -178,6 +178,27 @@ describe("createFileSet", () => {
       "bar.js": {}
     });
   });
+
+  it("should unify windows- and posix paths into posix paths", () => {
+    const result = createFileSet(
+      [
+        {
+          filePath: "\\absolute\\path\\windows\\foo.js",
+          messages: []
+        },
+        {
+          filePath: "/absolute/path/posix/bar.js",
+          messages: []
+        }
+      ],
+      []
+    );
+
+    expect(result).toEqual({
+      "windows/foo.js": {},
+      "posix/bar.js": {}
+    });
+  });
 });
 
 describe("cleanUpDeletedFilesInFileSet", () => {
diff --git a/__tests__/integration/engine/run.test.js b/__tests__/integration/engine/run.test.js
index d694773..f5ec2dd 100644
--- a/__tests__/integration/engine/run.test.js
+++ b/__tests__/integration/engine/run.test.js
@@ -134,6 +134,20 @@ describe("engine.run", () => {
     })
   );
 
+  it(
+    "should convert windows- to posix paths when reading a record",
+    setup("windows-paths-in-record", ({ fixturePath }) => {
+      const { run } = require("../../../lib/engine");
+      const { results } = run({}, ["."]);
+      expect(results).toHaveLength(0);
+
+      const rewrittenRecord = readRecord(fixturePath);
+      expect(rewrittenRecord.files).toEqual({
+        "src/main.js": { "no-console": 1 }
+      });
+    })
+  );
+
   it(
     "ignores eslint rules not listed in config",
     setup("no-rules", () => {
diff --git a/__tests__/integration/fixtures/windows-paths-in-record/.eslintrc.js b/__tests__/integration/fixtures/windows-paths-in-record/.eslintrc.js
new file mode 100644
index 0000000..cadf14e
--- /dev/null
+++ b/__tests__/integration/fixtures/windows-paths-in-record/.eslintrc.js
@@ -0,0 +1,5 @@
+module.exports = {
+  rules: {
+    "no-console": "warn"
+  }
+};
diff --git a/__tests__/integration/fixtures/windows-paths-in-record/.esplint.rec.json b/__tests__/integration/fixtures/windows-paths-in-record/.esplint.rec.json
new file mode 100644
index 0000000..685fedd
--- /dev/null
+++ b/__tests__/integration/fixtures/windows-paths-in-record/.esplint.rec.json
@@ -0,0 +1,9 @@
+{
+  "recordVersion": 1,
+  "configHash": "773a8b36f5d74ada1b0144c983a6d725c71c9413",
+  "files": {
+    "src\\main.js": {
+      "no-console": 1
+    }
+  }
+}
diff --git a/__tests__/integration/fixtures/windows-paths-in-record/.esplintrc.js b/__tests__/integration/fixtures/windows-paths-in-record/.esplintrc.js
new file mode 100644
index 0000000..6727cec
--- /dev/null
+++ b/__tests__/integration/fixtures/windows-paths-in-record/.esplintrc.js
@@ -0,0 +1,4 @@
+module.exports = {
+  surfaceArea: ["."],
+  rules: ["no-console"]
+};
diff --git a/__tests__/integration/fixtures/windows-paths-in-record/src/main.js b/__tests__/integration/fixtures/windows-paths-in-record/src/main.js
new file mode 100644
index 0000000..f741f0b
--- /dev/null
+++ b/__tests__/integration/fixtures/windows-paths-in-record/src/main.js
@@ -0,0 +1 @@
+console.log("this does nothing");
diff --git a/__tests__/pathUtils.test.js b/__tests__/pathUtils.test.js
new file mode 100644
index 0000000..323b219
--- /dev/null
+++ b/__tests__/pathUtils.test.js
@@ -0,0 +1,31 @@
+const { toPosixPath, toSystemPath, toWinPath } = require("../lib/pathUtils");
+const helpers = require("../lib/helpers");
+
+describe("toPosixPath", function() {
+  it("should convert windows to posix paths", () => {
+    expect(toPosixPath("\\windows\\path")).toEqual("/windows/path");
+  });
+  it("should not alter posix paths", () => {
+    expect(toPosixPath("/posix/path")).toEqual("/posix/path");
+  });
+});
+
+describe("toWinPath", function() {
+  it("should convert posix to windows path", () => {
+    expect(toWinPath("/posix/path")).toEqual("\\posix\\path");
+  });
+  it("not alter windows path", () => {
+    expect(toWinPath("\\windows\\path")).toEqual("\\windows\\path");
+  });
+});
+
+describe("toSystemPath", () => {
+  it("should convert posix to windows on windows", () => {
+    jest.spyOn(helpers, "isPosix").mockImplementation(() => false);
+    expect(toSystemPath("/posix/path")).toEqual("\\posix\\path");
+  });
+  it("should convert windows to posix on posix", () => {
+    jest.spyOn(helpers, "isPosix").mockImplementation(() => true);
+    expect(toSystemPath("\\windows\\path")).toEqual("/windows/path");
+  });
+});
diff --git a/__tests__/record.test.js b/__tests__/record.test.js
index d49b6c6..0187c5b 100644
--- a/__tests__/record.test.js
+++ b/__tests__/record.test.js
@@ -1,4 +1,4 @@
-const { createRecord } = require("../lib/record");
+const { createRecord, unifyFilePaths } = require("../lib/record");
 jest.mock("../package.json", () => ({ version: "1.0.0" }));
 
 describe("createRecord", () => {
@@ -28,3 +28,34 @@ describe("createRecord", () => {
     expect(Object.keys(files)).toEqual(["a/b/c", "b/b/c", "z/a/c"]);
   });
 });
+
+describe("unifyFilePaths", () => {
+  it("converts windows paths to posix", () => {
+    const record = {
+      hash: "aabbcc",
+      files: {
+        "\\windows\\path.js": {},
+        "\\another\\windows\\path.js": {}
+      }
+    };
+    const unifiedRecord = unifyFilePaths(record);
+    expect(unifiedRecord).toEqual({
+      hash: "aabbcc",
+      files: {
+        "/windows/path.js": {},
+        "/another/windows/path.js": {}
+      }
+    });
+  });
+  it("keeps posix paths as posix", () => {
+    const record = {
+      hash: "aabbcc",
+      files: {
+        "/windows/path.js": {},
+        "/another/windows/path.js": {}
+      }
+    };
+    const unifiedRecord = unifyFilePaths(record);
+    expect(unifiedRecord).toEqual(record);
+  });
+});
diff --git a/lib/fileSet.js b/lib/fileSet.js
index 3c1f013..c35605a 100644
--- a/lib/fileSet.js
+++ b/lib/fileSet.js
@@ -1,13 +1,16 @@
 const path = require("path");
 const fs = require("fs");
 const chalk = require("chalk");
+const { toPosixPath, toSystemPath } = require("./pathUtils");
 
 function createFileSet(results, trackedRules, getWarnings) {
   const fileSet = {};
   const trackedRuleSet = new Set(trackedRules);
 
   results.forEach(({ messages, filePath }) => {
-    const relativePath = path.relative(process.cwd(), filePath);
+    const relativePath = toPosixPath(
+      path.relative(process.cwd(), toSystemPath(filePath))
+    );
     const rules = {};
 
     if (getWarnings) {
diff --git a/lib/helpers.js b/lib/helpers.js
new file mode 100644
index 0000000..80d8158
--- /dev/null
+++ b/lib/helpers.js
@@ -0,0 +1,9 @@
+const path = require("path");
+
+function isPosix() {
+  return path.sep === path.posix.sep;
+}
+
+module.exports = {
+  isPosix
+};
diff --git a/lib/pathUtils.js b/lib/pathUtils.js
new file mode 100644
index 0000000..1676d82
--- /dev/null
+++ b/lib/pathUtils.js
@@ -0,0 +1,24 @@
+const path = require("path");
+const helpers = require("./helpers");
+
+function toPosixPath(filePath) {
+  return filePath.split(path.win32.sep).join(path.posix.sep);
+}
+
+function toWinPath(filePath) {
+  return filePath.split(path.posix.sep).join(path.win32.sep);
+}
+
+function toSystemPath(filePath) {
+  if (helpers.isPosix()) {
+    return toPosixPath(filePath);
+  } else {
+    return toWinPath(filePath);
+  }
+}
+
+module.exports = {
+  toPosixPath,
+  toWinPath,
+  toSystemPath
+};
diff --git a/lib/record.js b/lib/record.js
index f7e8c27..b3f2306 100644
--- a/lib/record.js
+++ b/lib/record.js
@@ -9,6 +9,7 @@ const semver = require("semver");
 const { hasGitConflict, resolveGitConflict } = require("./gitConflict");
 const EsplintError = require("./EsplintError");
 const git = require("simple-git/promise")();
+const { toPosixPath } = require("./pathUtils");
 
 function getRecordPath() {
   const packageDir = pkgDir.sync();
@@ -38,6 +39,23 @@ function createRecord({ files, config }) {
   };
 }
 
+function unifyFilePaths(record) {
+  if (record === null) {
+    return record;
+  }
+
+  return {
+    ...record,
+    files: Object.entries(record.files).reduce(
+      (result, [filePath, warnings]) => {
+        result[toPosixPath(filePath)] = warnings;
+        return result;
+      },
+      {}
+    )
+  };
+}
+
 function getRecord(config) {
   const { overwrite } = config;
 
@@ -47,7 +65,7 @@ function getRecord(config) {
   }
 
   const configHash = getConfigHash(config);
-  const record = readRecord();
+  const record = unifyFilePaths(readRecord());
 
   if (record === null) {
     return {};
@@ -165,5 +183,6 @@ module.exports = {
   getRecord,
   writeRecord,
   readRecord,
-  stageRecord
+  stageRecord,
+  unifyFilePaths
 };