diff --git a/lib/eslint/eslint-helpers.js b/lib/eslint/eslint-helpers.js
index 9bfd751cb2b..e25b10e8bc4 100644
--- a/lib/eslint/eslint-helpers.js
+++ b/lib/eslint/eslint-helpers.js
@@ -795,7 +795,7 @@ function processOptions({
         // when overrideConfigFile is true that means don't do config file lookup
         configFile: overrideConfigFile === true ? false : overrideConfigFile,
         overrideConfig,
-        cwd,
+        cwd: path.normalize(cwd),
         errorOnUnmatchedPattern,
         fix,
         fixTypes,
diff --git a/lib/eslint/eslint.js b/lib/eslint/eslint.js
index e1d2116944e..15e6b3dee41 100644
--- a/lib/eslint/eslint.js
+++ b/lib/eslint/eslint.js
@@ -289,7 +289,7 @@ function processOptions({
         cacheLocation,
         cacheStrategy,
         configFile: overrideConfigFile,
-        cwd,
+        cwd: path.normalize(cwd),
         errorOnUnmatchedPattern,
         extensions,
         fix,
diff --git a/tests/fixtures/example-app3/.eslintignore b/tests/fixtures/example-app3/.eslintignore
new file mode 100644
index 00000000000..e5999645160
--- /dev/null
+++ b/tests/fixtures/example-app3/.eslintignore
@@ -0,0 +1 @@
+src/dist
diff --git a/tests/fixtures/example-app3/.eslintrc.js b/tests/fixtures/example-app3/.eslintrc.js
new file mode 100644
index 00000000000..86a595d362c
--- /dev/null
+++ b/tests/fixtures/example-app3/.eslintrc.js
@@ -0,0 +1,9 @@
+module.exports = {
+    parserOptions: {
+      ecmaVersion: 2020,
+    },
+    'root': true,
+    'rules': {
+      'semi': 'error',
+    },
+  };
diff --git a/tests/fixtures/example-app3/eslint.config.js b/tests/fixtures/example-app3/eslint.config.js
new file mode 100644
index 00000000000..7f94a016cdc
--- /dev/null
+++ b/tests/fixtures/example-app3/eslint.config.js
@@ -0,0 +1,10 @@
+module.exports = [
+    {
+        ignores: ["src/dist"]
+    },
+    {
+        rules: {
+            semi: "error"
+        }
+    }
+];
diff --git a/tests/fixtures/example-app3/node_modules/eslint-formatter-cwd/index.js b/tests/fixtures/example-app3/node_modules/eslint-formatter-cwd/index.js
new file mode 100644
index 00000000000..ca853b3a44d
--- /dev/null
+++ b/tests/fixtures/example-app3/node_modules/eslint-formatter-cwd/index.js
@@ -0,0 +1 @@
+module.exports = (_, { cwd }) => cwd;
diff --git a/tests/fixtures/example-app3/node_modules/eslint-formatter-cwd/package.json b/tests/fixtures/example-app3/node_modules/eslint-formatter-cwd/package.json
new file mode 100644
index 00000000000..0967ef424bc
--- /dev/null
+++ b/tests/fixtures/example-app3/node_modules/eslint-formatter-cwd/package.json
@@ -0,0 +1 @@
+{}
diff --git a/tests/fixtures/example-app3/node_modules/eslint-plugin-test/index.js b/tests/fixtures/example-app3/node_modules/eslint-plugin-test/index.js
new file mode 100644
index 00000000000..50d288c6101
--- /dev/null
+++ b/tests/fixtures/example-app3/node_modules/eslint-plugin-test/index.js
@@ -0,0 +1,19 @@
+module.exports = {
+    rules: {
+        "report-cwd": {
+            meta: {
+                schema: []
+            },
+            create(context) {
+                return {
+                    Program(node) {
+                        context.report({
+                            node,
+                            message: context.cwd
+                        });
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/tests/fixtures/example-app3/node_modules/eslint-plugin-test/package.json b/tests/fixtures/example-app3/node_modules/eslint-plugin-test/package.json
new file mode 100644
index 00000000000..0967ef424bc
--- /dev/null
+++ b/tests/fixtures/example-app3/node_modules/eslint-plugin-test/package.json
@@ -0,0 +1 @@
+{}
diff --git a/tests/fixtures/example-app3/src/1.js b/tests/fixtures/example-app3/src/1.js
new file mode 100644
index 00000000000..e14c4f2a956
--- /dev/null
+++ b/tests/fixtures/example-app3/src/1.js
@@ -0,0 +1 @@
+console.log(1)
diff --git a/tests/fixtures/example-app3/src/dist/2.js b/tests/fixtures/example-app3/src/dist/2.js
new file mode 100644
index 00000000000..32926e25ddb
--- /dev/null
+++ b/tests/fixtures/example-app3/src/dist/2.js
@@ -0,0 +1 @@
+console.log(2)
diff --git a/tests/lib/eslint/eslint.js b/tests/lib/eslint/eslint.js
index a422f4b867f..cb43823fbc5 100644
--- a/tests/lib/eslint/eslint.js
+++ b/tests/lib/eslint/eslint.js
@@ -126,6 +126,28 @@ describe("ESLint", () => {
             }
         });
 
+        it("should normalize 'options.cwd'.", async () => {
+            const cwd = getFixturePath("example-app3");
+            const engine = new ESLint({
+                cwd: `${cwd}${path.sep}foo${path.sep}..`, // `<cwd>/foo/..` should be normalized to `<cwd>`
+                useEslintrc: false,
+                overrideConfig: {
+                    plugins: ["test"],
+                    rules: {
+                        "test/report-cwd": "error"
+                    }
+                }
+            });
+            const results = await engine.lintText("");
+
+            assert.strictEqual(results[0].messages[0].ruleId, "test/report-cwd");
+            assert.strictEqual(results[0].messages[0].message, cwd);
+
+            const formatter = await engine.loadFormatter("cwd");
+
+            assert.strictEqual(formatter.format(results), cwd);
+        });
+
         it("should report one fatal message when given a path by --ignore-path that is not a file when ignore is true.", () => {
             assert.throws(() => {
                 // eslint-disable-next-line no-new -- Check for throwing
@@ -6945,4 +6967,50 @@ describe("ESLint", () => {
             });
         });
     });
+
+    // only works on a Windows machine
+    if (os.platform() === "win32") {
+
+        // https://github.com/eslint/eslint/issues/17042
+        describe("with cwd that is using forward slash on Windows", () => {
+            const cwd = getFixturePath("example-app3");
+            const cwdForwardSlash = cwd.replace(/\\/gu, "/");
+
+            it("should correctly handle ignore patterns", async () => {
+                const engine = new ESLint({ cwd: cwdForwardSlash });
+                const results = await engine.lintFiles(["./src"]);
+
+                // src/dist/2.js should be ignored
+                assert.strictEqual(results.length, 1);
+                assert.strictEqual(results[0].filePath, path.join(cwd, "src\\1.js"));
+            });
+
+            it("should pass cwd with backslashes to rules", async () => {
+                const engine = new ESLint({
+                    cwd: cwdForwardSlash,
+                    useEslintrc: false,
+                    overrideConfig: {
+                        plugins: ["test"],
+                        rules: {
+                            "test/report-cwd": "error"
+                        }
+                    }
+                });
+                const results = await engine.lintText("");
+
+                assert.strictEqual(results[0].messages[0].ruleId, "test/report-cwd");
+                assert.strictEqual(results[0].messages[0].message, cwd);
+            });
+
+            it("should pass cwd with backslashes to formatters", async () => {
+                const engine = new ESLint({
+                    cwd: cwdForwardSlash
+                });
+                const results = await engine.lintText("");
+                const formatter = await engine.loadFormatter("cwd");
+
+                assert.strictEqual(formatter.format(results), cwd);
+            });
+        });
+    }
 });
diff --git a/tests/lib/eslint/flat-eslint.js b/tests/lib/eslint/flat-eslint.js
index ffad0a793ea..0a692e9e7f9 100644
--- a/tests/lib/eslint/flat-eslint.js
+++ b/tests/lib/eslint/flat-eslint.js
@@ -140,6 +140,30 @@ describe("FlatESLint", () => {
             }
         });
 
+        it("should normalize 'options.cwd'.", async () => {
+            const cwd = getFixturePath("example-app3");
+            const engine = new FlatESLint({
+                cwd: `${cwd}${path.sep}foo${path.sep}..`, // `<cwd>/foo/..` should be normalized to `<cwd>`
+                overrideConfigFile: true,
+                overrideConfig: {
+                    plugins: {
+                        test: require(path.join(cwd, "node_modules", "eslint-plugin-test"))
+                    },
+                    rules: {
+                        "test/report-cwd": "error"
+                    }
+                }
+            });
+            const results = await engine.lintText("");
+
+            assert.strictEqual(results[0].messages[0].ruleId, "test/report-cwd");
+            assert.strictEqual(results[0].messages[0].message, cwd);
+
+            const formatter = await engine.loadFormatter("cwd");
+
+            assert.strictEqual(formatter.format(results), cwd);
+        });
+
         // https://github.com/eslint/eslint/issues/2380
         it("should not modify baseConfig when format is specified", () => {
             const customBaseConfig = { root: true };
@@ -5701,6 +5725,54 @@ describe("FlatESLint", () => {
         });
     });
 
+    // only works on a Windows machine
+    if (os.platform() === "win32") {
+
+        // https://github.com/eslint/eslint/issues/17042
+        describe("with cwd that is using forward slash on Windows", () => {
+            const cwd = getFixturePath("example-app3");
+            const cwdForwardSlash = cwd.replace(/\\/gu, "/");
+
+            it("should correctly handle ignore patterns", async () => {
+                const engine = new FlatESLint({ cwd: cwdForwardSlash });
+                const results = await engine.lintFiles(["./src"]);
+
+                // src/dist/2.js should be ignored
+                assert.strictEqual(results.length, 1);
+                assert.strictEqual(results[0].filePath, path.join(cwd, "src\\1.js"));
+            });
+
+            it("should pass cwd with backslashes to rules", async () => {
+                const engine = new FlatESLint({
+                    cwd: cwdForwardSlash,
+                    overrideConfigFile: true,
+                    overrideConfig: {
+                        plugins: {
+                            test: require(path.join(cwd, "node_modules", "eslint-plugin-test"))
+                        },
+                        rules: {
+                            "test/report-cwd": "error"
+                        }
+                    }
+                });
+                const results = await engine.lintText("");
+
+                assert.strictEqual(results[0].messages[0].ruleId, "test/report-cwd");
+                assert.strictEqual(results[0].messages[0].message, cwd);
+            });
+
+            it("should pass cwd with backslashes to formatters", async () => {
+                const engine = new FlatESLint({
+                    cwd: cwdForwardSlash
+                });
+                const results = await engine.lintText("");
+                const formatter = await engine.loadFormatter("cwd");
+
+                assert.strictEqual(formatter.format(results), cwd);
+            });
+        });
+    }
+
 });
 
 describe("shouldUseFlatConfig", () => {