diff --git a/extensions/ql-vscode/src/config.ts b/extensions/ql-vscode/src/config.ts
index 774bd17b4..eebd0687a 100644
--- a/extensions/ql-vscode/src/config.ts
+++ b/extensions/ql-vscode/src/config.ts
@@ -292,14 +292,13 @@ export function isCanary() {
  */
 export const NO_CACHE_AST_VIEWER = new Setting('disableCache', AST_VIEWER_SETTING);
 
-/*
+/**
  * Lists of GitHub repositories that you want to query remotely via the "Run Remote query" command.
  * Note: This command is only available for internal users.
  * 
  * This setting should be a JSON object where each key is a user-specified name (string),
  * and the value is an array of GitHub repositories (of the form `<owner>/<repo>`).
  */
-
 const REMOTE_REPO_LISTS = new Setting('remoteRepositoryLists', ROOT_SETTING);
 
 export function getRemoteRepositoryLists(): Record<string, string[]> | undefined {
diff --git a/extensions/ql-vscode/src/run-remote-query.ts b/extensions/ql-vscode/src/run-remote-query.ts
index 01bce7e27..7f150b614 100644
--- a/extensions/ql-vscode/src/run-remote-query.ts
+++ b/extensions/ql-vscode/src/run-remote-query.ts
@@ -69,7 +69,7 @@ async function getRepositories(): Promise<string[] | undefined> {
         placeHolder: 'Select a repository list. You can define repository lists in the `codeQL.remoteRepositoryLists` setting.',
         ignoreFocusOut: true,
       });
-    if (quickpick && quickpick.repoList.length > 0) {
+    if (quickpick?.repoList.length) {
       void logger.log(`Selected repositories: ${quickpick.repoList}`);
       return quickpick.repoList;
     } else {
@@ -78,6 +78,7 @@ async function getRepositories(): Promise<string[] | undefined> {
     }
   } else {
     void logger.log('No repository lists defined. Displaying text input box.');
+    const repoRegex = /^(?:[a-zA-Z0-9]+-?)*[a-zA-Z0-9]\/[a-zA-Z0-9-_]+$/;
     const remoteRepo = await window.showInputBox({
       title: 'Enter a GitHub repository in the format <owner>/<repo> (e.g. github/codeql)',
       placeHolder: '<owner>/<repo>',
@@ -87,6 +88,9 @@ async function getRepositories(): Promise<string[] | undefined> {
     if (!remoteRepo) {
       void showAndLogErrorMessage('No repositories entered.');
       return;
+    } else if (!repoRegex.test(remoteRepo)) { // Check if user entered invalid input
+      void showAndLogErrorMessage('Invalid repository format. Must be in the format <owner>/<repo> (e.g. github/codeql)');
+      return;
     }
     void logger.log(`Entered repository: ${remoteRepo}`);
     return [remoteRepo];