diff --git a/README.md b/README.md
index adea8a2..4cefb62 100644
--- a/README.md
+++ b/README.md
@@ -51,9 +51,11 @@ Property                               | Description
 `rubyTestExplorer.logfile`             | Write diagnostic logs to the given file.
 `rubyTestExplorer.testFramework`       | `none`, `auto`, `rspec`, or `minitest`. `auto` by default, which automatically detects the test framework based on the gems listed by Bundler. Can disable the extension functionality with `none` or set the test framework explicitly, if auto-detect isn't working properly.
 `rubyTestExplorer.filePattern`         | Define the pattern to match test files by, for example `["*_test.rb", "test_*.rb", "*_spec.rb"]`.
+`rubyTestExplorer.debugger`            | Which debugger to use. `rdebug-ide` or `rdbg`.
 `rubyTestExplorer.debuggerHost`        | Define the host to connect the debugger to, for example `127.0.0.1`.
 `rubyTestExplorer.debuggerPort`        | Define the port to connect the debugger to, for example `1234`.
 `rubyTestExplorer.debugCommand`        | Define how to run rdebug-ide, for example `rdebug-ide` or `bundle exec rdebug-ide`.
+`rubyTestExplorer.rdbgCommand`         | Define how to run rdbg, for example `rdbg` or `bundle exec rdbg`.
 `rubyTestExplorer.rspecCommand`        | Define the command to run RSpec tests with, for example `bundle exec rspec`, `spring rspec`, or `rspec`.
 `rubyTestExplorer.rspecDirectory`      | Define the relative directory of the specs in a given workspace, for example `./spec/`.
 `rubyTestExplorer.minitestCommand`     | Define how to run Minitest with Rake, for example `./bin/rake`, `bundle exec rake` or `rake`. Must be a Rake command.
diff --git a/package.json b/package.json
index b7fa0d4..9c03969 100644
--- a/package.json
+++ b/package.json
@@ -141,6 +141,20 @@
           },
           "scope": "resource"
         },
+        "rubyTestExplorer.debugger": {
+          "description": "Which debugger to use. `rdebug-ide` or `rdbg`.",
+          "type": "string",
+          "default": "rdebug-ide",
+          "enum": [
+            "rdebug-ide",
+            "rdbg"
+          ],
+          "enumDescriptions": [
+            "Use ruby-debug-ide gem.",
+            "Use debug gem."
+          ],
+          "scope": "resource"
+        },
         "rubyTestExplorer.debuggerHost": {
           "markdownDescription": "The host to connect the debugger to.",
           "default": "127.0.0.1",
@@ -158,6 +172,12 @@
           "default": "rdebug-ide",
           "type": "string",
           "scope": "resource"
+        },
+        "rubyTestExplorer.rdbgCommand": {
+          "markdownDescription": "Define how to run rdbg, for example `rdbg` or `bundle exec rdbg`.",
+          "default": "rdbg",
+          "type": "string",
+          "scope": "resource"
         }
       }
     }
diff --git a/src/adapter.ts b/src/adapter.ts
index 89a705c..3a79164 100644
--- a/src/adapter.ts
+++ b/src/adapter.ts
@@ -72,21 +72,17 @@ export class RubyAdapter implements TestAdapter {
   async debug(testsToRun: string[]): Promise<void> {
     this.log.info(`Debugging test(s) ${JSON.stringify(testsToRun)} of ${this.workspace.uri.fsPath}`);
 
-    const config = vscode.workspace.getConfiguration('rubyTestExplorer', null)
-
-    const debuggerConfig = {
-      name: "Debug Ruby Tests",
-      type: "Ruby",
-      request: "attach",
-      remoteHost: config.get('debuggerHost') || "127.0.0.1",
-      remotePort: config.get('debuggerPort') || "1234",
-      remoteWorkspaceRoot: "${workspaceRoot}"
+    let debuggerConfig: vscode.DebugConfiguration;
+    try {
+      debuggerConfig = this.getDebuggerConfig();
+    } catch (err) {
+      this.log.error('Failed to get debugger configuration', err);
+      return;
     }
-
     const testRunPromise = this.run(testsToRun, debuggerConfig);
 
     this.log.info('Starting the debug session');
-    let debugSession: any;
+    let debugSession: vscode.DebugSession;
     try {
       await this.testsInstance!.debugCommandStarted()
       debugSession = await this.startDebugging(debuggerConfig);
@@ -103,6 +99,11 @@ export class RubyAdapter implements TestAdapter {
       subscription.dispose();
     });
 
+    if (vscode.workspace.getConfiguration('rubyTestExplorer', null).get('debugger') === 'rdbg') {
+      // debug gem is configured to stop at load, so we resume the execution on attach.
+      debugSession.customRequest('continue');
+    }
+
     await testRunPromise;
   }
 
@@ -220,6 +221,44 @@ export class RubyAdapter implements TestAdapter {
     return vscode.debug.onDidTerminateDebugSession(cb);
   }
 
+  private getDebuggerConfig(): vscode.DebugConfiguration {
+    const config = vscode.workspace.getConfiguration('rubyTestExplorer', null)
+
+    switch (config.get('debugger')) {
+      case 'rdebug-ide': {
+        return {
+          name: "Debug Ruby Tests",
+          type: "Ruby",
+          request: "attach",
+          remoteHost: config.get('debuggerHost') || "127.0.0.1",
+          remotePort: config.get('debuggerPort') || "1234",
+          remoteWorkspaceRoot: "${workspaceRoot}"
+        }
+      }
+      case 'rdbg': {
+        const debuggerHost = config.get('debuggerHost') || "127.0.0.1";
+        const debuggerPort = config.get('debuggerPort') || "1234";
+
+        // Debugger configuration to attach by using KoichiSasada.vscode-rdbg.
+        // See: https://marketplace.visualstudio.com/items?itemName=KoichiSasada.vscode-rdbg
+        return {
+          name: "Debug Ruby Tests",
+          type: "rdbg",
+          request: "attach",
+          localfs: true,
+          debugPort: `${debuggerHost}:${debuggerPort}`,
+
+          // These parameters are used to lanuch the debug server.
+          debuggerHost,
+          debuggerPort,
+        }
+      }
+
+      default:
+        throw new Error("Invalid debugger");
+    }
+  }
+
   /**
    * Get the test directory based on the configuration value if there's a configured test framework.
    */
diff --git a/src/minitestTests.ts b/src/minitestTests.ts
index da92249..534faba 100644
--- a/src/minitestTests.ts
+++ b/src/minitestTests.ts
@@ -70,13 +70,9 @@ export class MinitestTests extends Tests {
    * @return The rdebug-ide command
    */
   protected getDebugCommand(debuggerConfig: vscode.DebugConfiguration): string {
-    let command: string =
-      (vscode.workspace.getConfiguration('rubyTestExplorer', null).get('debugCommand') as string) ||
-      'rdebug-ide';
-
-    return (
-      `${command}  --host ${debuggerConfig.remoteHost} --port ${debuggerConfig.remotePort}` +
-      ` -- ${process.platform == 'win32' ? '%EXT_DIR%' : '$EXT_DIR'}/debug_minitest.rb`
+    return this.buildDebugCommand(
+      debuggerConfig,
+      `${process.platform == 'win32' ? '%EXT_DIR%' : '$EXT_DIR'}/debug_minitest.rb`
     );
   }
 
diff --git a/src/rspecTests.ts b/src/rspecTests.ts
index 12217ca..05e178d 100644
--- a/src/rspecTests.ts
+++ b/src/rspecTests.ts
@@ -88,13 +88,10 @@ export class RspecTests extends Tests {
    * @return The rdebug-ide command
    */
   protected getDebugCommand(debuggerConfig: vscode.DebugConfiguration, args: string): string {
-    let command: string =
-      (vscode.workspace.getConfiguration('rubyTestExplorer', null).get('debugCommand') as string) ||
-      'rdebug-ide';
-
-    return (
-      `${command} --host ${debuggerConfig.remoteHost} --port ${debuggerConfig.remotePort}` +
-      ` -- ${process.platform == 'win32' ? '%EXT_DIR%' : '$EXT_DIR'}/debug_rspec.rb ${args}`
+    return this.buildDebugCommand(
+      debuggerConfig,
+      `${process.platform == 'win32' ? '%EXT_DIR%' : '$EXT_DIR'}/debug_rspec.rb`,
+      args
     );
   }
   /**
@@ -192,7 +189,8 @@ export class RspecTests extends Tests {
     this.log.info(`Running test file: ${testFile}`);
     const spawnArgs: childProcess.SpawnOptions = {
       cwd: this.workspace.uri.fsPath,
-      shell: true
+      shell: true,
+      env: this.getProcessEnv()
     };
 
     // Run tests for a given file at once with a single command.
@@ -217,7 +215,8 @@ export class RspecTests extends Tests {
     this.log.info(`Running full test suite.`);
     const spawnArgs: childProcess.SpawnOptions = {
       cwd: this.workspace.uri.fsPath,
-      shell: true
+      shell: true,
+      env: this.getProcessEnv()
     };
 
     let testCommand = this.testCommandWithFormatterAndDebugger(debuggerConfig);
diff --git a/src/tests.ts b/src/tests.ts
index ce29bd3..10f1368 100644
--- a/src/tests.ts
+++ b/src/tests.ts
@@ -366,7 +366,7 @@ export abstract class Tests {
     this.currentChildProcess.stderr!.pipe(split2()).on('data', (data) => {
       data = data.toString();
       this.log.debug(`[CHILD PROCESS OUTPUT] ${data}`);
-      if (data.startsWith('Fast Debugger') && this.debugCommandStartedResolver) {
+      if ((data.startsWith('Fast Debugger') || data.includes("DEBUGGER: wait for debugger connection...")) && this.debugCommandStartedResolver) {
         this.debugCommandStartedResolver()
       }
     });
@@ -519,6 +519,46 @@ export abstract class Tests {
     return this.context.asAbsolutePath('./ruby');
   }
 
+  /**
+   * Get the user-configured rdebug-ide command, if there is one.
+   *
+   * @param debuggerConfig A VS Code debugger configuration.
+   * @return The debugger command
+   */
+  protected buildDebugCommand(debuggerConfig: vscode.DebugConfiguration, initFile: string, args?: string): string {
+    switch (debuggerConfig.type) {
+      case "Ruby": { // ruby-debug-ide gem
+        const debugCommand: string =
+          (vscode.workspace.getConfiguration('rubyTestExplorer', null).get('debugCommand') as string) ||
+          'rdebug-ide';
+
+        let command = `${debugCommand} --host ${debuggerConfig.remoteHost} --port ${debuggerConfig.remotePort} -- ${initFile}`
+        if (args) {
+          command += ` ${args}`
+        }
+
+        return command;
+      }
+      case "rdbg": { // debug gem
+        const debugCommand: string =
+          (vscode.workspace.getConfiguration('rubyTestExplorer', null).get('rdbgCommand') as string) ||
+          'rdbg';
+        const host = debuggerConfig.debuggerHost as string;
+        const port = debuggerConfig.debuggerPort as string;
+
+        let command = `${debugCommand} --open --stop-at-load --host ${host} --port ${port} -- ${initFile}`
+        if (args) {
+          command += ` ${args}`
+        }
+
+        return command;
+      }
+      default:
+        throw "Unknown debugger"
+    }
+
+  }
+
   /**
    * Runs a single test.
    *