diff --git a/src/mongo_client.ts b/src/mongo_client.ts
index b35d2811bf..1e0971cb8c 100644
--- a/src/mongo_client.ts
+++ b/src/mongo_client.ts
@@ -435,10 +435,14 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> {
 
     if (options.tls) {
       if (typeof options.tlsCAFile === 'string') {
-        options.ca ??= await fs.readFile(options.tlsCAFile, { encoding: 'utf8' });
+        options.ca ??= await fs.readFile(options.tlsCAFile);
       }
       if (typeof options.tlsCertificateKeyFile === 'string') {
-        options.key ??= await fs.readFile(options.tlsCertificateKeyFile, { encoding: 'utf8' });
+        if (!options.key || !options.cert) {
+          const contents = await fs.readFile(options.tlsCertificateKeyFile);
+          options.key ??= contents;
+          options.cert ??= contents;
+        }
       }
     }
     if (typeof options.srvHost === 'string') {
@@ -787,6 +791,7 @@ export interface MongoOptions
    * |:----------------------|:----------------------------------------------|:-------------------|
    * | `ca`                  | `tlsCAFile`                                   | `string`           |
    * | `crl`                 | N/A                                           | `string`           |
+   * | `cert`                | `tlsCertificateKeyFile`                       | `string`           |
    * | `key`                 | `tlsCertificateKeyFile`                       | `string`           |
    * | `passphrase`          | `tlsCertificateKeyFilePassword`               | `string`           |
    * | `rejectUnauthorized`  | `tlsAllowInvalidCertificates`                 | `boolean`          |
@@ -804,9 +809,9 @@ export interface MongoOptions
    *
    * The files specified by the paths passed in to the `tlsCAFile` and `tlsCertificateKeyFile` fields
    * are read lazily on the first call to `MongoClient.connect`. Once these files have been read and
-   * the `ca` and `key` fields are populated, they will not be read again on subsequent calls to
-   * `MongoClient.connect`. As a result, until the first call to `MongoClient.connect`, the `ca`
-   * and `key` fields will be undefined.
+   * the `ca`, `cert` and `key` fields are populated, they will not be read again on subsequent calls to
+   * `MongoClient.connect`. As a result, until the first call to `MongoClient.connect`, the `ca`,
+   * `cert` and `key` fields will be undefined.
    */
   tls: boolean;
 
diff --git a/test/manual/tls_support.test.ts b/test/manual/tls_support.test.ts
index 179527b1c4..f50c43a48d 100644
--- a/test/manual/tls_support.test.ts
+++ b/test/manual/tls_support.test.ts
@@ -1,7 +1,12 @@
 import { expect } from 'chai';
 import { promises as fs } from 'fs';
 
-import { LEGACY_HELLO_COMMAND, MongoClient, type MongoClientOptions } from '../mongodb';
+import {
+  LEGACY_HELLO_COMMAND,
+  MongoClient,
+  type MongoClientOptions,
+  MongoServerSelectionError
+} from '../mongodb';
 
 const REQUIRED_ENV = ['MONGODB_URI', 'SSL_KEY_FILE', 'SSL_CA_FILE'];
 
@@ -51,11 +56,13 @@ describe('TLS Support', function () {
         expect(client.options).property('tlsCertificateKeyFile', TLS_CERT_KEY_FILE);
         expect(client.options).not.have.property('ca');
         expect(client.options).not.have.property('key');
+        expect(client.options).not.have.property('cert');
 
         await client.connect();
 
         expect(client.options).property('ca').to.exist;
         expect(client.options).property('key').to.exist;
+        expect(client.options).property('cert').to.exist;
       });
 
       context('when client has been opened and closed more than once', function () {
@@ -106,6 +113,44 @@ describe('TLS Support', function () {
       });
     });
   });
+
+  context('when tlsCertificateKeyFile is provided, but tlsCAFile is missing', () => {
+    let client: MongoClient;
+    beforeEach(() => {
+      client = new MongoClient(CONNECTION_STRING, {
+        tls: true,
+        tlsCertificateKeyFile: TLS_CERT_KEY_FILE,
+        serverSelectionTimeoutMS: 5000,
+        connectTimeoutMS: 5000
+      });
+    });
+    afterEach(async () => {
+      if (client) await client.close();
+    });
+
+    it('throws a MongoServerSelectionError', async () => {
+      const err = await client.connect().catch(e => e);
+      expect(err).to.be.instanceOf(MongoServerSelectionError);
+    });
+  });
+
+  context('when tlsCAFile is provided, but tlsCertificateKeyFile is missing', () => {
+    let client: MongoClient;
+    beforeEach(() => {
+      client = new MongoClient(CONNECTION_STRING, {
+        tls: true,
+        tlsCAFile: TLS_CA_FILE
+      });
+    });
+    afterEach(async () => {
+      if (client) await client.close();
+    });
+
+    it('connects without error', async () => {
+      const clientOrError = await client.connect().catch(e => e);
+      expect(clientOrError).to.be.instanceOf(MongoClient);
+    });
+  });
 });
 
 function makeConnectionTest(connectionString: string, clientOptions?: MongoClientOptions) {
diff --git a/test/unit/mongo_client.test.js b/test/unit/mongo_client.test.js
index 64ec92e2fe..c43a8a17ba 100644
--- a/test/unit/mongo_client.test.js
+++ b/test/unit/mongo_client.test.js
@@ -58,6 +58,7 @@ describe('MongoOptions', function () {
     expect(options).to.not.have.property('tlsCertificateKeyFilePassword');
     expect(options).to.not.have.property('key');
     expect(options).to.not.have.property('ca');
+    expect(options).to.not.have.property('cert');
     expect(options).to.have.property('tlsCertificateKeyFile', filename);
     expect(options).to.have.property('tlsCAFile', filename);
     expect(options).has.property('passphrase', 'tlsCertificateKeyFilePassword');