diff --git a/src/CommandLine/Core/Tokenizer.cs b/src/CommandLine/Core/Tokenizer.cs
index 902b65e4..e0e09fd3 100644
--- a/src/CommandLine/Core/Tokenizer.cs
+++ b/src/CommandLine/Core/Tokenizer.cs
@@ -6,6 +6,7 @@
 using CommandLine.Infrastructure;
 using CSharpx;
 using RailwaySharp.ErrorHandling;
+using System.Text.RegularExpressions;
 
 namespace CommandLine.Core
 {
@@ -188,9 +189,19 @@ private static IEnumerable<Token> TokenizeLongName(
                     onError(new BadFormatTokenError(value));
                     yield break;
                 }
-                var parts = text.Split('=');
-                yield return Token.Name(parts[0]);
-                yield return Token.Value(parts[1], true);
+
+                var tokenMatch = Regex.Match(text, "^([^=]+)=([^ ].*)$");
+
+                if (tokenMatch.Success)
+                {
+                    yield return Token.Name(tokenMatch.Groups[1].Value);
+                    yield return Token.Value(tokenMatch.Groups[2].Value, true);
+                }
+                else
+                {
+                    onError(new BadFormatTokenError(value));
+                    yield break;
+                }
             }
         }
     }
diff --git a/tests/CommandLine.Tests/Unit/Core/TokenizerTests.cs b/tests/CommandLine.Tests/Unit/Core/TokenizerTests.cs
index 37dbe51f..bceb1ea0 100644
--- a/tests/CommandLine.Tests/Unit/Core/TokenizerTests.cs
+++ b/tests/CommandLine.Tests/Unit/Core/TokenizerTests.cs
@@ -92,6 +92,41 @@ public void Normalize_should_remove_all_value_with_explicit_assignment_of_existi
 
             // Teardown
         }
+
+        [Fact]
+        public void Should_properly_parse_option_with_equals_in_value()
+        {
+            /**
+             * This is how the arg. would look in `static void Main(string[] args)`
+             * if passed from the command-line and the option-value wrapped in quotes.
+             * Ex.) ./app --connectionString="Server=localhost;Data Source..."
+             */
+            var args = new[] { "--connectionString=Server=localhost;Data Source=(LocalDB)\v12.0;Initial Catalog=temp;" };
+
+            var result = Tokenizer.Tokenize(args, name => NameLookupResult.OtherOptionFound, token => token);
+
+            var tokens = result.SucceededWith();
+
+            Assert.NotNull(tokens);
+            Assert.Equal(2, tokens.Count());
+            Assert.Equal("connectionString", tokens.First().Text);
+            Assert.Equal("Server=localhost;Data Source=(LocalDB)\v12.0;Initial Catalog=temp;", tokens.Last().Text);
+        }
+
+        [Fact]
+        public void Should_return_error_if_option_format_with_equals_is_not_correct()
+        {
+            var args = new[] { "--option1 = fail", "--option2= fail" };
+
+            var result = Tokenizer.Tokenize(args, name => NameLookupResult.OtherOptionFound, token => token);
+
+            var tokens = result.SuccessfulMessages();
+
+            Assert.NotNull(tokens);
+            Assert.Equal(2, tokens.Count());
+            Assert.Equal(ErrorType.BadFormatTokenError, tokens.First().Tag);
+            Assert.Equal(ErrorType.BadFormatTokenError, tokens.Last().Tag);
+        }
     }
    
 }