diff --git a/lib/connection_string.js b/lib/connection_string.js
index b468a3b014..1aaf85f6f0 100644
--- a/lib/connection_string.js
+++ b/lib/connection_string.js
@@ -523,7 +523,7 @@ function assertTlsOptionsAreEqual(optionName, queryString, queryStringKeys) {
       const firstValue = queryString[optionName][0];
       queryString[optionName].forEach(tlsValue => {
         if (tlsValue !== firstValue) {
-          throw new MongoParseError('All values of ${optionName} must be the same.');
+          throw new MongoParseError(`All values of ${optionName} must be the same.`);
         }
       });
     }
diff --git a/test/unit/core/connection_string.test.js b/test/unit/core/connection_string.test.js
index 3ddb05b7e2..470a9a7a33 100644
--- a/test/unit/core/connection_string.test.js
+++ b/test/unit/core/connection_string.test.js
@@ -203,6 +203,13 @@ describe('Connection String', function() {
         done();
       });
     });
+
+    it('should validate non-equal tls values', function(done) {
+      parseConnectionString('mongodb://localhost/?tls=true&tls=false', err => {
+        expect(err).to.have.property('message', 'All values of tls must be the same.');
+        done();
+      });
+    });
   });
 
   describe('spec tests', function() {