diff --git a/action.yml b/action.yml
index 1530a81..9d422c3 100644
--- a/action.yml
+++ b/action.yml
@@ -20,10 +20,18 @@ inputs:
     description: "A string which, if present in a git commit, indicates that a change represents a major (breaking) change. Wrap with '/' to match using a regular expression."
     required: true
     default: "(MAJOR)"
+  major_regexp_flags:
+    description: "A string which indicates the flags used by the `major_pattern` regular expression. Supported flags: idgs"
+    required: false
+    default: ""
   minor_pattern:
     description: "A string which, if present in a git commit, indicates that a change represents a minor (feature) change. Wrap with '/' to match using a regular expression."
     required: true
     default: "(MINOR)"
+  minor_regexp_flags:
+    description: "A string which indicates the flags used by the `minor_pattern` regular expression. Supported flags: idgs"
+    required: false
+    default: ""
   version_format:
     description: "Pattern to use when formatting output version"
     required: true
diff --git a/dist/index.js b/dist/index.js
index 7c35a7c..9f889ce 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -407,6 +407,8 @@ function run() {
             useBranches: core.getInput('use_branches') === 'true',
             majorPattern: core.getInput('major_pattern'),
             minorPattern: core.getInput('minor_pattern'),
+            majorFlags: core.getInput('major_flags'),
+            minorFlags: core.getInput('minor_flags'),
             versionFormat: core.getInput('version_format'),
             changePath: core.getInput('change_path'),
             namespace: core.getInput('namespace'),
diff --git a/lib/ActionConfig.js b/lib/ActionConfig.js
index ecefae7..2babbf8 100644
--- a/lib/ActionConfig.js
+++ b/lib/ActionConfig.js
@@ -12,8 +12,12 @@ class ActionConfig {
         this.useBranches = false;
         /** A string which, if present in a git commit, indicates that a change represents a major (breaking) change. Wrap with '/' to match using a regular expression. */
         this.majorPattern = "(MAJOR)";
+        /** A string which indicates the flags used by the `majorPattern` regular expression. */
+        this.majorFlags = "(MAJOR)";
         /** A string which, if present in a git commit, indicates that a change represents a minor (feature) change. Wrap with '/' to match using a regular expression. */
         this.minorPattern = "(MINOR)";
+        /** A string which indicates the flags used by the `minorPattern` regular expression. */
+        this.minorFlags = "(MINOR)";
         /** Pattern to use when formatting output version */
         this.versionFormat = '${major}.${minor}.${patch}';
         /** Path to check for changes. If any changes are detected in the path the 'changed' output will true. Enter multiple paths separated by spaces. */
diff --git a/lib/main.js b/lib/main.js
index 779421e..675d6fa 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -66,6 +66,8 @@ function run() {
             useBranches: core.getInput('use_branches') === 'true',
             majorPattern: core.getInput('major_pattern'),
             minorPattern: core.getInput('minor_pattern'),
+            majorFlags: core.getInput('major_regexp_flags'),
+            minorFlags: core.getInput('minor_regexp_flags'),
             versionFormat: core.getInput('version_format'),
             changePath: core.getInput('change_path'),
             namespace: core.getInput('namespace'),
diff --git a/lib/providers/DefaultVersionClassifier.js b/lib/providers/DefaultVersionClassifier.js
index 27e2460..32d00d8 100644
--- a/lib/providers/DefaultVersionClassifier.js
+++ b/lib/providers/DefaultVersionClassifier.js
@@ -15,12 +15,12 @@ const VersionType_1 = require("./VersionType");
 class DefaultVersionClassifier {
     constructor(config) {
         const searchBody = config.searchCommitBody;
-        this.majorPattern = this.parsePattern(config.majorPattern, searchBody);
-        this.minorPattern = this.parsePattern(config.minorPattern, searchBody);
+        this.majorPattern = this.parsePattern(config.majorPattern, config.majorFlags, searchBody);
+        this.minorPattern = this.parsePattern(config.minorPattern, config.minorFlags, searchBody);
     }
-    parsePattern(pattern, searchBody) {
+    parsePattern(pattern, flags, searchBody) {
         if (pattern.startsWith('/') && pattern.endsWith('/')) {
-            var regex = new RegExp(pattern.slice(1, -1));
+            var regex = new RegExp(pattern.slice(1, -1), flags);
             return searchBody ?
                 (commit) => regex.test(commit.subject) || regex.test(commit.body) :
                 (commit) => regex.test(commit.subject);
diff --git a/package.json b/package.json
index 71d330e..52a20fa 100644
--- a/package.json
+++ b/package.json
@@ -5,8 +5,8 @@
   "main": "lib/main.js",
   "scripts": {
     "build": "tsc",
-    "format": "prettier --write '**/*.ts'",
-    "format-check": "prettier --check '**/*.ts'",
+    "format": "prettier --write **/**.ts",
+    "format-check": "prettier --check **/**.ts",
     "lint": "eslint src/**/*.ts",
     "package": "ncc build --source-map --license licenses.txt",
     "test": "jest --config ./jest.config.js",
diff --git a/readme.md b/readme.md
index fbb3fbe..29084eb 100644
--- a/readme.md
+++ b/readme.md
@@ -86,8 +86,12 @@ it will be given the new version if the build were to be retriggered, for exampl
     # A string which, if present in a git commit, indicates that a change represents a
     # major (breaking) change, supports regular expressions wrapped with '/'
     major_pattern: "(MAJOR)"
+    # A string which indicates the flags used by the `major_pattern` regular expression. Supported flags: idgs
+    major_regexp_flags: ""
     # Same as above except indicating a minor change, supports regular expressions wrapped with '/'
     minor_pattern: "(MINOR)"
+    # A string which indicates the flags used by the `minor_pattern` regular expression. Supported flags: idgs
+    minor_regexp_flags: ""
     # A string to determine the format of the version output
     format: "${major}.${minor}.${patch}-prerelease${increment}"
     # Optional path to check for changes. If any changes are detected in the path the
diff --git a/src/ActionConfig.ts b/src/ActionConfig.ts
index 0dbefcd..980d3f2 100644
--- a/src/ActionConfig.ts
+++ b/src/ActionConfig.ts
@@ -8,8 +8,12 @@ export class ActionConfig {
     public useBranches: boolean = false;
     /** A string which, if present in a git commit, indicates that a change represents a major (breaking) change. Wrap with '/' to match using a regular expression. */
     public majorPattern: string = "(MAJOR)";
+    /** A string which indicates the flags used by the `majorPattern` regular expression. */
+    public majorFlags: string = "";
     /** A string which, if present in a git commit, indicates that a change represents a minor (feature) change. Wrap with '/' to match using a regular expression. */
     public minorPattern: string = "(MINOR)";
+    /** A string which indicates the flags used by the `minorPattern` regular expression. */
+    public minorFlags: string = "";
     /** Pattern to use when formatting output version */
     public versionFormat: string = '${major}.${minor}.${patch}';
     /** Path to check for changes. If any changes are detected in the path the 'changed' output will true. Enter multiple paths separated by spaces. */
diff --git a/src/main.test.ts b/src/main.test.ts
index 0cc029e..36e5fb1 100644
--- a/src/main.test.ts
+++ b/src/main.test.ts
@@ -472,6 +472,22 @@ test('Regular expressions can be used as minor tag', async () => {
     expect((await repo.runAction()).formattedVersion).toBe('0.1.0+0');
 }, 15000);
 
+test('Regular expressions and flags can be used as major tag', async () => {
+    const repo = createTestRepo({ tagPrefix: '', majorPattern: '/s[a-z]+value/', majorFlags: 'i' }); // 0.0.1
+
+    repo.makeCommit('Initial Commit'); // 0.0.1+0
+    repo.makeCommit('Second Commit SomeValue'); // 1.0.0+0
+    expect((await repo.runAction()).formattedVersion).toBe('1.0.0+0');
+}, 15000);
+
+test('Regular expressions and flags can be used as minor tag', async () => {
+    const repo = createTestRepo({ tagPrefix: '', minorPattern: '/s[a-z]+value/', minorFlags: 'i' }); // 0.0.1
+
+    repo.makeCommit('Initial Commit'); // 0.0.1+0
+    repo.makeCommit('Second Commit SomeValue'); // 0.0.1+1
+    expect((await repo.runAction()).formattedVersion).toBe('0.1.0+0');
+}, 15000);
+
 test('Tag prefix can include forward slash', async () => {
     const repo = createTestRepo({ tagPrefix: 'version/' }); // 0.0.0
 
diff --git a/src/main.ts b/src/main.ts
index 1ad981a..4f1bdba 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -39,6 +39,8 @@ export async function run() {
     useBranches: core.getInput('use_branches') === 'true',
     majorPattern: core.getInput('major_pattern'),
     minorPattern: core.getInput('minor_pattern'),
+    majorFlags: core.getInput('major_regexp_flags'),
+    minorFlags: core.getInput('minor_regexp_flags'),
     versionFormat: core.getInput('version_format'),
     changePath: core.getInput('change_path'),
     namespace: core.getInput('namespace'),
diff --git a/src/providers/DefaultVersionClassifier.ts b/src/providers/DefaultVersionClassifier.ts
index 66a8136..1ab3d39 100644
--- a/src/providers/DefaultVersionClassifier.ts
+++ b/src/providers/DefaultVersionClassifier.ts
@@ -13,13 +13,13 @@ export class DefaultVersionClassifier implements VersionClassifier {
 
     constructor(config: ActionConfig) {
         const searchBody = config.searchCommitBody;
-        this.majorPattern = this.parsePattern(config.majorPattern, searchBody);
-        this.minorPattern = this.parsePattern(config.minorPattern, searchBody);
+        this.majorPattern = this.parsePattern(config.majorPattern, config.majorFlags, searchBody);
+        this.minorPattern = this.parsePattern(config.minorPattern, config.minorFlags, searchBody);
     }
 
-    protected parsePattern(pattern: string, searchBody: boolean): (pattern: CommitInfo) => boolean {
+    protected parsePattern(pattern: string, flags: string, searchBody: boolean): (pattern: CommitInfo) => boolean {
         if (pattern.startsWith('/') && pattern.endsWith('/')) {
-            var regex = new RegExp(pattern.slice(1, -1));
+            var regex = new RegExp(pattern.slice(1, -1), flags);
             return searchBody ?
                 (commit: CommitInfo) => regex.test(commit.subject) || regex.test(commit.body) :
                 (commit: CommitInfo) => regex.test(commit.subject);