diff --git a/resources/UNICORN-UPPERCASE.PNG b/resources/UNICORN-UPPERCASE.PNG
new file mode 100644
index 0000000..6169ed9
Binary files /dev/null and b/resources/UNICORN-UPPERCASE.PNG differ
diff --git a/src/utils.ts b/src/utils.ts
index 2efdb97..5261454 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -43,7 +43,7 @@ export async function getFileType(
    */
   const magicType = await fileTypeFromBuffer(fileContents)
   if (magicType) {
-    return Object.assign({ ext: magicType.ext }, parseMimeType(magicType.mime))
+    return Object.assign({ ext: magicType.ext.toLowerCase() }, parseMimeType(magicType.mime))
   }
 
   return null
@@ -61,7 +61,7 @@ export function computeFileTypeFromName(
    * and pull type/subtype from the headers content type.
    */
   return Object.assign(
-    { ext: extname(clientName).replace(/^\./, '') },
+    { ext: extname(clientName).replace(/^\./, '').toLowerCase() },
     parseMimeType(headers['content-type'])
   )
 }
diff --git a/tests/body_parser.spec.ts b/tests/body_parser.spec.ts
index 747af5b..2e0a0a2 100644
--- a/tests/body_parser.spec.ts
+++ b/tests/body_parser.spec.ts
@@ -26,7 +26,12 @@ import { AppFactory } from '@adonisjs/application/factories'
 import { Multipart } from '../src/multipart/main.ts'
 import { type MultipartFile } from '../src/multipart/file.ts'
 import { BodyParserMiddlewareFactory } from '../factories/middleware_factory.ts'
-import { packageFilePath, packageFileSize, unicornFilePath } from './helpers.ts'
+import {
+  packageFilePath,
+  packageFileSize,
+  unicornFilePath,
+  unicornUppercaseFilePath,
+} from './helpers.ts'
 
 test.group('BodyParser Middleware', () => {
   test('do not parse get requests', async ({ assert }) => {
@@ -1189,6 +1194,40 @@ test.group('BodyParser Middleware | multipart', () => {
     ])
   })
 
+  test('validate uppercase file extension', async ({ assert }) => {
+    const server = createServer(async (req, res) => {
+      const request = new RequestFactory().merge({ req, res }).create()
+      const response = new ResponseFactory().merge({ req, res }).create()
+      const ctx = new HttpContextFactory().merge({ request, response }).create()
+      const middleware = new BodyParserMiddlewareFactory().create()
+
+      await middleware.handle(ctx, async () => {
+        res.writeHead(200, { 'content-type': 'application/json' })
+        const pkgFile = ctx.request.file('image')!
+        pkgFile.sizeLimit = 100_000
+        pkgFile.validate()
+
+        pkgFile.allowedExtensions = ['png']
+        pkgFile.validate()
+
+        res.end(
+          JSON.stringify({
+            tmpPath: pkgFile.tmpPath!,
+            size: pkgFile.size,
+            validated: pkgFile.validated,
+            isValid: pkgFile.isValid,
+            errors: pkgFile.errors,
+          })
+        )
+      })
+    })
+
+    const { body } = await supertest(server).post('/').attach('image', unicornUppercaseFilePath)
+    assert.exists(body.tmpPath)
+    assert.isTrue(body.validated)
+    assert.isTrue(body.isValid)
+  })
+
   test('calling validate multiple times must be a noop', async ({ assert }) => {
     const server = createServer(async (req, res) => {
       const request = new RequestFactory().merge({ req, res }).create()
diff --git a/tests/helpers.ts b/tests/helpers.ts
index 3ac190f..4be990a 100644
--- a/tests/helpers.ts
+++ b/tests/helpers.ts
@@ -18,6 +18,9 @@ export const largePdfFile = fileURLToPath(
 export const xlsFilePath = fileURLToPath(new URL('../resources/sample.xls', import.meta.url))
 export const xlsxFilePath = fileURLToPath(new URL('../resources/sample.xlsx', import.meta.url))
 export const unicornFilePath = fileURLToPath(new URL('../resources/unicorn.png', import.meta.url))
+export const unicornUppercaseFilePath = fileURLToPath(
+  new URL('../resources/UNICORN-UPPERCASE.PNG', import.meta.url)
+)
 export const unicornNoExtFilePath = fileURLToPath(
   new URL('../resources/unicorn-wo-ext', import.meta.url)
 )
diff --git a/tests/multipart.spec.ts b/tests/multipart.spec.ts
index cd7889b..cfebb1f 100644
--- a/tests/multipart.spec.ts
+++ b/tests/multipart.spec.ts
@@ -32,6 +32,7 @@ import {
   packageFileSize,
   unicornFilePath,
   unicornNoExtFilePath,
+  unicornUppercaseFilePath,
 } from './helpers.ts'
 
 const BASE_URL = new URL('./tmp/', import.meta.url)
@@ -639,6 +640,42 @@ test.group('Multipart', () => {
     ])
   })
 
+  test('does not report extension validation errors when file extension is uppercase', async ({
+    assert,
+  }) => {
+    let files: null | Record<string, MultipartFile | MultipartFile[]> = null
+    const server = createServer(async (req, res) => {
+      const request = new RequestFactory().merge({ req, res }).create()
+      const response = new ResponseFactory().merge({ req, res }).create()
+      const ctx = new HttpContextFactory().merge({ request, response }).create()
+      const multipart = new Multipart(ctx, { maxFields: 1000, limit: 100_000 })
+
+      multipart.onFile(
+        '*',
+        {
+          extnames: ['png'],
+        },
+        (part, reporter) => {
+          return new Promise((resolve, reject) => {
+            part.on('error', reject)
+            part.on('end', resolve)
+            part.on('data', reporter)
+          })
+        }
+      )
+
+      await multipart.process()
+      files = ctx.request['__raw_files'] || null
+      res.end()
+    })
+
+    await supertest(server).post('/').attach('image', unicornUppercaseFilePath)
+
+    assert.property(files, 'image')
+    assert.isTrue(files!.image instanceof MultipartFile && files!.image.isValid)
+    assert.equal(files!.image instanceof MultipartFile && files!.image.state, 'consumed')
+  })
+
   test('do not run validations when deferValidations is set to true', async ({ assert }) => {
     let files: null | Record<string, MultipartFile | MultipartFile[]> = null
     const server = createServer(async (req, res) => {
@@ -928,6 +965,50 @@ test.group('Multipart', () => {
     assert.lengthOf(report.errors, 0)
   })
 
+  test('validates uppercase extension', async ({ assert }) => {
+    let files: null | Record<string, MultipartFile | MultipartFile[]> = null
+    const server = createServer(async (req, res) => {
+      const request = new RequestFactory().merge({ req, res }).create()
+      const response = new ResponseFactory().merge({ req, res }).create()
+      const ctx = new HttpContextFactory().merge({ request, response }).create()
+      const multipart = new Multipart(ctx, { maxFields: 1000, limit: 100_000 })
+
+      multipart.onFile(
+        '*',
+        {
+          extnames: ['png'],
+        },
+        (part, reporter) => {
+          return new Promise((resolve, reject) => {
+            part.on('error', reject)
+            part.on('end', resolve)
+            part.on('data', reporter)
+          })
+        }
+      )
+
+      try {
+        await multipart.process()
+      } catch (error) {
+        console.log(error)
+      }
+      files = ctx.request['__raw_files'] || null
+      res.end()
+    })
+
+    await supertest(server).post('/').attach('image', unicornUppercaseFilePath)
+
+    assert.property(files, 'image')
+    assert.instanceOf(files!.image, MultipartFile)
+
+    const image = files!.image as MultipartFile
+
+    assert.isTrue(image.isValid)
+    assert.equal(image.state, 'consumed')
+    assert.equal(image.extname, 'png')
+    assert.lengthOf(image.errors, 0)
+  })
+
   test('process medium sized files', async ({ assert }) => {
     let files: null | Record<string, MultipartFile | MultipartFile[]> = null