diff --git a/CHANGELOG.md b/CHANGELOG.md
index dbd757bb..a6ea8af1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+v5.1.21
+------
+* Add a new base class for tests called BaseEngineParSeqTest.java to allow test suite execution in parallel (with no race conditions).
+
 v5.1.20
 ------
 * Upgrade bytebuddy and asm version for JDK 17 and JDK 21 support
diff --git a/build.gradle b/build.gradle
index c0000b03..caa066fe 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,5 +1,7 @@
 buildscript {
   repositories {
+    mavenCentral()
+    gradlePluginPortal()
     maven {
       url "https://plugins.gradle.org/m2/"
     }
@@ -155,4 +157,4 @@ subprojects { p ->
 project.tasks.uploadArchives.doFirst {
   logger.lifecycle "Cleaning local ivy repo: $rootDir/build/ivy-repo"
   delete(file("$rootDir/build/ivy-repo"))
-}
\ No newline at end of file
+}
diff --git a/subprojects/parseq-test-api/src/main/java/com/linkedin/parseq/BaseEngineParSeqTest.java b/subprojects/parseq-test-api/src/main/java/com/linkedin/parseq/BaseEngineParSeqTest.java
new file mode 100644
index 00000000..86e34a9e
--- /dev/null
+++ b/subprojects/parseq-test-api/src/main/java/com/linkedin/parseq/BaseEngineParSeqTest.java
@@ -0,0 +1,155 @@
+/*
+ * Copyright 2025 LinkedIn, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.linkedin.parseq;
+
+import com.linkedin.parseq.Engine;
+import com.linkedin.parseq.ParSeqUnitTestHelper;
+import com.linkedin.parseq.Task;
+import java.util.concurrent.TimeUnit;
+import javax.annotation.Nonnull;
+import org.testng.annotations.AfterSuite;
+import org.testng.annotations.BeforeSuite;
+
+/**
+ * This is a custom implementation of {@link com.linkedin.parseq.BaseEngineTest}. This custom
+ * implementation is necessary to avoid race-conditions that we have in BaseEngineTest when running tests
+ * in parallel. It's a variant of {@link com.linkedin.parseq.BaseEngineTest}, and has the following
+ * differences:
+ *
+ * <p>1) Setup and tearDown are executed at test-suite level. Whereas {@link
+ * com.linkedin.parseq.BaseEngineTest} executes setup()/teardown() at class level (which can cause
+ * race-conditions if two or more tests from the same class are executed in parallel).
+ *
+ * <p>2) It uses mutex locking mechanism to set up and tear down {@link ParSeqUnitTestHelper} to
+ * avoid race-condition on ParSeqUnitTestHelper instance (it's a common resource among tests).
+ *
+ * <p>3) Default timeout for runAndWait() method is 10 seconds (which is needed by majority of the tests).
+ * Tests can override this by using the runAndWait() method that accepts timeout param.
+ *
+ */
+public class BaseEngineParSeqTest {
+  private static final Object MUTEX = new Object();
+  private static final int RUN_AND_WAIT_TIMEOUT_SECONDS = 10;
+  private static final ParSeqUnitTestHelper PAR_SEQ_UNIT_TEST_HELPER = new ParSeqUnitTestHelper();
+
+  /*
+   * Get ParSeqUnitTestHelper
+   *
+   * @return ParSeqUnitTestHelper instance.
+   */
+  protected static ParSeqUnitTestHelper getParSeqUnitTestHelper() {
+    return PAR_SEQ_UNIT_TEST_HELPER;
+  }
+
+  /**
+   * Setup ParSeqUnitTestHelper
+   *
+   * @throws Exception
+   */
+  @BeforeSuite
+  public void setUpParSeqHelper() throws Exception {
+    synchronized (MUTEX) {
+      getParSeqUnitTestHelper().setUp();
+    }
+  }
+
+  /**
+   * Tear down ParSeqUnitTestHelper
+   *
+   * @throws Exception
+   */
+  @AfterSuite
+  public void tearDownParSeqHelper() throws Exception {
+    synchronized (MUTEX) {
+      if (getParSeqUnitTestHelper().getEngine() != null) {
+        getParSeqUnitTestHelper().tearDown();
+      } else {
+        throw new RuntimeException(
+            "Tried to shut down Engine but it either has not even been created or "
+                + "has already been shut down, in "
+                + this.getClass().getName());
+      }
+    }
+  }
+
+  /**
+   * Run a parseq task and wait for it to complete, including all side-effects (e.g.
+   * Task.withSafeSideEffect). The latter is necessary to run tests in parallel without any
+   * race-conditions.
+   *
+   * <p>Uses a default timeout (10 seconds).
+   *
+   * @param <T> The type of the task.
+   * @param task The task to run.
+   * @return The same task after task completion, it is safe to call task.get() after running this
+   *     method.
+   */
+  protected <T> T runAndWait(@Nonnull Task<T> task) {
+    return runAndWait(task, RUN_AND_WAIT_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+  }
+
+  /**
+   * Run a parseq task and wait for it to complete, including all side-effects (e.g.
+   * Task.withSafeSideEffect). The latter is necessary to run tests in parallel without any
+   * race-conditions.
+   *
+   * <p>Uses a custom timeout provided by the caller.
+   *
+   * @param <T> The type of the task.
+   * @param task The task to run.
+   * @param timeOut the amount of time to wait for task completion.
+   * @param timeUnit the timeUnit (seconds, milliseconds, etc) for timeOut param.
+   * @return The same task after task completion, it is safe to call task.get() after running this
+   *     method.
+   */
+  protected <T> T runAndWait(@Nonnull Task<T> task, int timeOut, @Nonnull TimeUnit timeUnit) {
+    synchronized (MUTEX) {
+      return getParSeqUnitTestHelper().runAndWaitForPlanToComplete(this.getClass().getName(), task, timeOut, timeUnit);
+    }
+  }
+
+  /**
+   * Run a parseq task and wait for it to complete, including all side-effects (e.g.
+   * Task.withSafeSideEffect). The latter is necessary to run tests in parallel without any
+   * race-conditions.
+   *
+   * <p>Also verify that the task threw an exception and then return that Exception.
+   *
+   * <p>Use a default timeout (10 seconds).
+   *
+   * @param task The Task that should be run.
+   * @param exceptionClass The class of Exception that should be thrown when the task completes.
+   * @param <T> The type of Exception that should be returned.
+   * @return The exception that was encountered while the Task was running.
+   */
+  protected <T extends Throwable> T runAndWaitException(@Nonnull Task<?> task, @Nonnull Class<T> exceptionClass) {
+    synchronized (MUTEX) {
+      return getParSeqUnitTestHelper()
+          .runAndWaitExceptionOnPlanCompletion(
+              this.getClass().getName(), task, exceptionClass, RUN_AND_WAIT_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+    }
+  }
+
+  /**
+   * Get the instance of parseq engine used for running tasks in tests.
+   *
+   * @return instance of {@link Engine} used for running tasks in tests.
+   */
+  protected Engine getEngine() {
+    return getParSeqUnitTestHelper().getEngine();
+  }
+}