diff --git a/Program.cs b/Program.cs
index d93bbc9..4e839b2 100644
--- a/Program.cs
+++ b/Program.cs
@@ -16,13 +16,20 @@ static class Program
                 );
         branchOption.AddAlias("-b");
 
+        var tagOption = new Option<string>(
+                "--tag",
+                "Specify the tag to filter by"
+                );
+        tagOption.AddAlias("-t");
+
         var rootCommand = new RootCommand("Get a tally of contributors' commits")
         {
             outputOption,
             branchOption,
+            tagOption,
         };
 
-        rootCommand.SetHandler((outputOptionValue, branchOptionValue) => {
+        rootCommand.SetHandler((outputOptionValue, branchOptionValue, tagOptionValue) => {
                     CommitDetail commits = new CommitDetail();
                     
                     switch (outputOptionValue) 
@@ -31,48 +38,78 @@ static class Program
                             StdOutDataService outDataService = new StdOutDataService();
                             DataAccess dataAccess = new DataAccess(outDataService);
 
-                            switch (branchOptionValue) 
-                            {
-                                case null:
-                                    commits.GetCurrentCommitsByName();
-                                    dataAccess.WriteData(commits.CommitDetails);
-                                    break;
-                                default:
-                                    commits.GetCommitsByBranch(branchOptionValue);
-                                    dataAccess.WriteData(commits.CommitDetails);
-                                    break;
+                            if (branchOptionValue != null && tagOptionValue != null) {
+                                Console.WriteLine("Please specify either a branch or a tag");
+                                Environment.Exit(2);
+                            } else if (branchOptionValue != null && tagOptionValue == null) {
+                                switch (branchOptionValue)
+                                {
+                                    case null:
+                                        commits.GetCurrentCommitsByName();
+                                        dataAccess.WriteData(commits.CommitDetails);
+                                        break;
+                                    default:
+                                        commits.GetCommitsByBranch(branchOptionValue);
+                                        dataAccess.WriteData(commits.CommitDetails);
+                                        break;
+                                }
+                                break;
+                            } else if (branchOptionValue == null && tagOptionValue != null) {
+                                commits.GetCommitsByTag(tagOptionValue);
+                                dataAccess.WriteData(commits.CommitDetails);
                             }
                             break;
                         case "xlsx":
                             ExcelDataService excelDataService = new ExcelDataService();
                             DataAccess dataAccessExcelCase = new DataAccess(excelDataService);
 
-                            switch (branchOptionValue)
-                            {
-                                case null:
-                                    commits.GetCurrentCommitsByName();
-                                    dataAccessExcelCase.WriteData(commits.CommitDetails);
-                                    break;
-                                default:
-                                    commits.GetCommitsByBranch(branchOptionValue);
-                                    dataAccessExcelCase.WriteData(commits.CommitDetails);
-                                    break;
+                            if (branchOptionValue != null && tagOptionValue != null) {
+                                Console.WriteLine("Please specify either a branch or a tag.");
+                                Environment.Exit(2);
+                            } else if (branchOptionValue != null && tagOptionValue == null) {
+                                switch (branchOptionValue)
+                                {
+                                    case null:
+                                        commits.GetCurrentCommitsByName();
+                                        dataAccessExcelCase.WriteData(commits.CommitDetails);
+                                        break;
+                                    default:
+                                        commits.GetCommitsByBranch(branchOptionValue);
+                                        dataAccessExcelCase.WriteData(commits.CommitDetails);
+                                        break;
+                                }
+                                break;
+                            } else if (branchOptionValue == null && tagOptionValue != null) {
+                                commits.GetCommitsByTag(tagOptionValue);
+                                dataAccessExcelCase.WriteData(commits.CommitDetails);
                             }
                             break;
                         case null:
                             StdOutDataService stdOutDataService = new StdOutDataService();
                             DataAccess dataAccessNullCase = new DataAccess(stdOutDataService);
 
-                            switch (branchOptionValue)
-                            {
-                                case null:
-                                    commits.GetCurrentCommitsByName();
-                                    dataAccessNullCase.WriteData(commits.CommitDetails);
-                                    break;
-                                default:
-                                    commits.GetCommitsByBranch(branchOptionValue);
-                                    dataAccessNullCase.WriteData(commits.CommitDetails);
-                                    break;
+                            if (branchOptionValue != null && tagOptionValue != null) {
+                                Console.WriteLine("Please specify either a branch or a tag.");
+                                Environment.Exit(2);
+                            } else if (branchOptionValue != null && tagOptionValue == null) {
+                                switch (branchOptionValue)
+                                {
+                                    case null:
+                                        commits.GetCurrentCommitsByName();
+                                        dataAccessNullCase.WriteData(commits.CommitDetails);
+                                        break;
+                                    default:
+                                        commits.GetCommitsByBranch(branchOptionValue);
+                                        dataAccessNullCase.WriteData(commits.CommitDetails);
+                                        break;
+                                }
+                                break;
+                            } else if (branchOptionValue == null && tagOptionValue != null) {
+                                commits.GetCommitsByTag(tagOptionValue);
+                                dataAccessNullCase.WriteData(commits.CommitDetails);
+                            } else {
+                                commits.GetCurrentCommitsByName();
+                                dataAccessNullCase.WriteData(commits.CommitDetails);
                             }
                             break;
                         default:
@@ -81,7 +118,7 @@ static class Program
                             break;
                     }
                 },
-                outputOption, branchOption);
+                outputOption, branchOption, tagOption);
 
         rootCommand.Invoke(args);
     }