diff --git a/java/com/google/gerrit/entities/SubmitRequirementExpression.java b/java/com/google/gerrit/entities/SubmitRequirementExpression.java
index 7b31304..0d51efd 100644
--- a/java/com/google/gerrit/entities/SubmitRequirementExpression.java
+++ b/java/com/google/gerrit/entities/SubmitRequirementExpression.java
@@ -45,5 +45,5 @@
   }
 
   /** Returns the underlying String representing this {@link SubmitRequirementExpression}. */
-  public abstract String expression();
+  public abstract String expressionString();
 }
diff --git a/java/com/google/gerrit/entities/SubmitRequirementExpressionResult.java b/java/com/google/gerrit/entities/SubmitRequirementExpressionResult.java
new file mode 100644
index 0000000..94c0e91
--- /dev/null
+++ b/java/com/google/gerrit/entities/SubmitRequirementExpressionResult.java
@@ -0,0 +1,146 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// 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.google.gerrit.entities;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
+import java.util.Optional;
+
+/** Result of evaluating a submit requirement expression on a given Change. */
+@AutoValue
+public abstract class SubmitRequirementExpressionResult {
+
+  /**
+   * Entity detailing the result of evaluating a Submit requirement expression. Contains an empty
+   * {@link Optional} if {@link #status()} is equal to {@link Status#ERROR}.
+   */
+  public abstract Optional<PredicateResult> predicateResult();
+
+  public abstract Optional<String> errorMessage();
+
+  public Status status() {
+    if (predicateResult().isPresent()) {
+      return predicateResult().get().status() ? Status.PASS : Status.FAIL;
+    }
+    return Status.ERROR;
+  }
+
+  public static SubmitRequirementExpressionResult create(PredicateResult predicateResult) {
+    return new AutoValue_SubmitRequirementExpressionResult(
+        Optional.of(predicateResult), Optional.empty());
+  }
+
+  public static SubmitRequirementExpressionResult error(String errorMessage) {
+    return new AutoValue_SubmitRequirementExpressionResult(
+        Optional.empty(), Optional.of(errorMessage));
+  }
+
+  /**
+   * Returns a list of leaf predicate results whose {@link PredicateResult#status()} is true. If
+   * {@link #status()} is equal to {@link Status#ERROR}, an empty list is returned.
+   */
+  public ImmutableList<PredicateResult> getPassingAtoms() {
+    if (predicateResult().isPresent()) {
+      return predicateResult().get().getAtoms(/* status= */ true);
+    }
+    return ImmutableList.of();
+  }
+
+  /**
+   * Returns a list of leaf predicate results whose {@link PredicateResult#status()} is false. If
+   * {@link #status()} is equal to {@link Status#ERROR}, an empty list is returned.
+   */
+  public ImmutableList<PredicateResult> getFailingAtoms() {
+    if (predicateResult().isPresent()) {
+      return predicateResult().get().getAtoms(/* status= */ false);
+    }
+    return ImmutableList.of();
+  }
+
+  public enum Status {
+    /** Submit requirement expression is fulfilled for a given change. */
+    PASS,
+
+    /** Submit requirement expression is failing for a given change. */
+    FAIL,
+
+    /** Submit requirement expression contains invalid syntax and is not parsable. */
+    ERROR
+  }
+
+  /**
+   * Entity detailing the result of evaluating a predicate.
+   *
+   * <p>Example - branch:refs/heads/foo and has:unresolved
+   *
+   * <p>The above predicate is an "And" predicate having two child predicates:
+   *
+   * <ul>
+   *   <li>branch:refs/heads/foo
+   *   <li>has:unresolved
+   * </ul>
+   *
+   * <p>Each child predicate as well as the parent contains the result of its evaluation.
+   */
+  @AutoValue
+  public abstract static class PredicateResult {
+    abstract ImmutableList<PredicateResult> childPredicateResults();
+
+    abstract String predicateString();
+
+    /** true if the predicate is passing for a given change. */
+    abstract boolean status();
+
+    /**
+     * Returns the list of leaf {@link PredicateResult} whose {@link #status()} is equal to the
+     * {@code status} parameter.
+     */
+    ImmutableList<PredicateResult> getAtoms(boolean status) {
+      ImmutableList.Builder<PredicateResult> atomsList = ImmutableList.builder();
+      getAtomsRecursively(atomsList, status);
+      return atomsList.build();
+    }
+
+    private void getAtomsRecursively(ImmutableList.Builder<PredicateResult> list, boolean status) {
+      if (childPredicateResults().isEmpty() && status() == status) {
+        list.add(this);
+        return;
+      }
+      childPredicateResults().forEach(c -> c.getAtomsRecursively(list, status));
+    }
+
+    public static Builder builder() {
+      return new AutoValue_SubmitRequirementExpressionResult_PredicateResult.Builder();
+    }
+
+    @AutoValue.Builder
+    public abstract static class Builder {
+      public abstract Builder childPredicateResults(ImmutableList<PredicateResult> value);
+
+      protected abstract ImmutableList.Builder<PredicateResult> childPredicateResultsBuilder();
+
+      public abstract Builder predicateString(String value);
+
+      public abstract Builder status(boolean value);
+
+      public Builder addChildPredicateResult(PredicateResult result) {
+        childPredicateResultsBuilder().add(result);
+        return this;
+      }
+
+      public abstract PredicateResult build();
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/cache/serialize/entities/SubmitRequirementSerializer.java b/java/com/google/gerrit/server/cache/serialize/entities/SubmitRequirementSerializer.java
index ad015d1..a76abdb 100644
--- a/java/com/google/gerrit/server/cache/serialize/entities/SubmitRequirementSerializer.java
+++ b/java/com/google/gerrit/server/cache/serialize/entities/SubmitRequirementSerializer.java
@@ -40,10 +40,10 @@
         .setName(submitRequirement.name())
         .setDescription(submitRequirement.description().orElse(""))
         .setApplicabilityExpression(
-            submitRequirement.applicabilityExpression().orElse(emptyExpression).expression())
-        .setBlockingExpression(submitRequirement.blockingExpression().expression())
+            submitRequirement.applicabilityExpression().orElse(emptyExpression).expressionString())
+        .setBlockingExpression(submitRequirement.blockingExpression().expressionString())
         .setOverrideExpression(
-            submitRequirement.overrideExpression().orElse(emptyExpression).expression())
+            submitRequirement.overrideExpression().orElse(emptyExpression).expressionString())
         .setAllowOverrideInChildProjects(submitRequirement.allowOverrideInChildProjects())
         .build();
   }
diff --git a/java/com/google/gerrit/server/project/ProjectConfig.java b/java/com/google/gerrit/server/project/ProjectConfig.java
index 5ac5ac7..dac1ac6 100644
--- a/java/com/google/gerrit/server/project/ProjectConfig.java
+++ b/java/com/google/gerrit/server/project/ProjectConfig.java
@@ -1694,19 +1694,19 @@
               SUBMIT_REQUIREMENT,
               name,
               KEY_SR_APPLICABILITY_EXPRESSION,
-              sr.applicabilityExpression().get().expression());
+              sr.applicabilityExpression().get().expressionString());
         }
         rc.setString(
             SUBMIT_REQUIREMENT,
             name,
             KEY_SR_BLOCKING_EXPRESSION,
-            sr.blockingExpression().expression());
+            sr.blockingExpression().expressionString());
         if (sr.overrideExpression().isPresent()) {
           rc.setString(
               SUBMIT_REQUIREMENT,
               name,
               KEY_SR_OVERRIDE_EXPRESSION,
-              sr.overrideExpression().get().expression());
+              sr.overrideExpression().get().expressionString());
         }
         rc.setBoolean(
             SUBMIT_REQUIREMENT,
diff --git a/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java
new file mode 100644
index 0000000..7fc1247
--- /dev/null
+++ b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java
@@ -0,0 +1,76 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// 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.google.gerrit.server.project;
+
+import com.google.gerrit.entities.SubmitRequirementExpression;
+import com.google.gerrit.entities.SubmitRequirementExpressionResult;
+import com.google.gerrit.entities.SubmitRequirementExpressionResult.PredicateResult;
+import com.google.gerrit.index.query.Predicate;
+import com.google.gerrit.index.query.QueryParseException;
+import com.google.gerrit.server.query.change.ChangeData;
+import com.google.gerrit.server.query.change.ChangeQueryBuilder;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+
+/** Evaluates submit requirements for different change data. */
+@Singleton
+public class SubmitRequirementsEvaluator {
+  private final Provider<ChangeQueryBuilder> changeQueryBuilderProvider;
+
+  @Inject
+  private SubmitRequirementsEvaluator(Provider<ChangeQueryBuilder> changeQueryBuilderProvider) {
+    this.changeQueryBuilderProvider = changeQueryBuilderProvider;
+  }
+
+  /**
+   * Validate a {@link SubmitRequirementExpression}. Callers who wish to validate submit
+   * requirements upon creation or update should use this method.
+   *
+   * @param expression entity containing the expression string.
+   * @throws QueryParseException the expression string contains invalid syntax and can't be parsed.
+   */
+  public void validateExpression(SubmitRequirementExpression expression)
+      throws QueryParseException {
+    changeQueryBuilderProvider.get().parse(expression.expressionString());
+  }
+
+  /** Evaluate a {@link SubmitRequirementExpression} using change data. */
+  public SubmitRequirementExpressionResult evaluateExpression(
+      SubmitRequirementExpression expression, ChangeData changeData) {
+    try {
+      Predicate<ChangeData> predicate =
+          changeQueryBuilderProvider.get().parse(expression.expressionString());
+      PredicateResult predicateResult = evaluatePredicateTree(predicate, changeData);
+      return SubmitRequirementExpressionResult.create(predicateResult);
+    } catch (QueryParseException e) {
+      return SubmitRequirementExpressionResult.error(e.getMessage());
+    }
+  }
+
+  /** Evaluate the predicate recursively using change data. */
+  private PredicateResult evaluatePredicateTree(
+      Predicate<ChangeData> predicate, ChangeData changeData) {
+    PredicateResult.Builder predicateResult =
+        PredicateResult.builder()
+            .predicateString(predicate.toString())
+            .status(predicate.asMatchable().match(changeData));
+    predicate
+        .getChildren()
+        .forEach(
+            c -> predicateResult.addChildPredicateResult(evaluatePredicateTree(c, changeData)));
+    return predicateResult.build();
+  }
+}
diff --git a/javatests/com/google/gerrit/acceptance/server/project/SubmitRequirementsEvaluatorIT.java b/javatests/com/google/gerrit/acceptance/server/project/SubmitRequirementsEvaluatorIT.java
new file mode 100644
index 0000000..19d0c97
--- /dev/null
+++ b/javatests/com/google/gerrit/acceptance/server/project/SubmitRequirementsEvaluatorIT.java
@@ -0,0 +1,108 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// 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.google.gerrit.acceptance.server.project;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.NoHttpd;
+import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.entities.SubmitRequirementExpression;
+import com.google.gerrit.entities.SubmitRequirementExpressionResult;
+import com.google.gerrit.entities.SubmitRequirementExpressionResult.PredicateResult;
+import com.google.gerrit.entities.SubmitRequirementExpressionResult.Status;
+import com.google.gerrit.server.project.SubmitRequirementsEvaluator;
+import com.google.gerrit.server.query.change.ChangeData;
+import com.google.inject.Inject;
+import java.util.Optional;
+import org.junit.Before;
+import org.junit.Test;
+
+@NoHttpd
+public class SubmitRequirementsEvaluatorIT extends AbstractDaemonTest {
+  @Inject SubmitRequirementsEvaluator evaluator;
+
+  private ChangeData changeData;
+
+  @Before
+  public void setUp() throws Exception {
+    PushOneCommit.Result pushResult =
+        createChange(testRepo, "refs/heads/master", "Fix a bug", "file.txt", "content", "topic");
+    changeData = pushResult.getChange();
+  }
+
+  @Test
+  public void invalidExpression() throws Exception {
+    SubmitRequirementExpression expression =
+        SubmitRequirementExpression.create("invalid_field:invalid_value");
+    SubmitRequirementExpressionResult result = evaluator.evaluateExpression(expression, changeData);
+
+    assertThat(result.status()).isEqualTo(Status.ERROR);
+    assertThat(result.errorMessage().get())
+        .isEqualTo("Unsupported operator invalid_field:invalid_value");
+  }
+
+  @Test
+  public void expressionWithPassingPredicate() throws Exception {
+    SubmitRequirementExpression expression =
+        SubmitRequirementExpression.create("branch:refs/heads/master");
+    SubmitRequirementExpressionResult result = evaluator.evaluateExpression(expression, changeData);
+
+    assertThat(result.status()).isEqualTo(Status.PASS);
+    assertThat(result.errorMessage()).isEqualTo(Optional.empty());
+  }
+
+  @Test
+  public void expressionWithFailingPredicate() throws Exception {
+    SubmitRequirementExpression expression =
+        SubmitRequirementExpression.create("branch:refs/heads/foo");
+    SubmitRequirementExpressionResult result = evaluator.evaluateExpression(expression, changeData);
+
+    assertThat(result.status()).isEqualTo(Status.FAIL);
+    assertThat(result.errorMessage()).isEqualTo(Optional.empty());
+  }
+
+  @Test
+  public void compositeExpression() throws Exception {
+    SubmitRequirementExpression expression =
+        SubmitRequirementExpression.create(
+            String.format(
+                "(project:%s AND branch:refs/heads/foo) OR message:\"Fix a bug\"", project.get()));
+
+    SubmitRequirementExpressionResult result = evaluator.evaluateExpression(expression, changeData);
+
+    assertThat(result.status()).isEqualTo(Status.PASS);
+
+    assertThat(result.getPassingAtoms())
+        .containsExactly(
+            PredicateResult.builder()
+                .predicateString(String.format("project:%s", project.get()))
+                .status(true)
+                .build(),
+            PredicateResult.builder()
+                .predicateString("message:\"Fix a bug\"")
+                .status(true)
+                .build());
+
+    assertThat(result.getFailingAtoms())
+        .containsExactly(
+            PredicateResult.builder()
+                // TODO(ghareeb): querying "branch:" creates a RefPredicate. Fix names so that they
+                // match
+                .predicateString(String.format("ref:refs/heads/foo"))
+                .status(false)
+                .build());
+  }
+}