diff --git a/src/Type/EntityQuery/EntityQueryDynamicReturnTypeExtension.php b/src/Type/EntityQuery/EntityQueryDynamicReturnTypeExtension.php
index 62b5acad..cdc5ef88 100644
--- a/src/Type/EntityQuery/EntityQueryDynamicReturnTypeExtension.php
+++ b/src/Type/EntityQuery/EntityQueryDynamicReturnTypeExtension.php
@@ -13,6 +13,7 @@
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\StringType;
 use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
 use function in_array;
 
 class EntityQueryDynamicReturnTypeExtension implements DynamicMethodReturnTypeExtension
@@ -66,6 +67,14 @@ public function getTypeFromMethodCall(
                     ? IntegerRangeType::createAllGreaterThanOrEqualTo(0)
                     : new EntityQueryExecuteWithoutAccessCheckCountType();
             }
+            if ($varType->isAggregate()) {
+                // An aggregate query returns a list of result rows, each keyed
+                // by the aggregate results and the groupBy columns.
+                $rowType = new ArrayType(new StringType(), TypeCombinator::addNull(new StringType()));
+                return $varType->hasAccessCheck()
+                    ? new ArrayType(new IntegerType(), $rowType)
+                    : new EntityQueryExecuteWithoutAccessCheckType(new IntegerType(), $rowType);
+            }
             if ($varType instanceof ConfigEntityQueryType) {
                 return $varType->hasAccessCheck()
                     ? new ArrayType(new StringType(), new StringType())
diff --git a/src/Type/EntityQuery/EntityQueryType.php b/src/Type/EntityQuery/EntityQueryType.php
index 9da78347..25aa1db5 100644
--- a/src/Type/EntityQuery/EntityQueryType.php
+++ b/src/Type/EntityQuery/EntityQueryType.php
@@ -13,6 +13,8 @@ class EntityQueryType extends ObjectType
 
     private bool $isCount = false;
 
+    private bool $isAggregate = false;
+
     public function hasAccessCheck(): bool
     {
         return $this->hasAccessCheck;
@@ -23,6 +25,11 @@ public function isCount(): bool
         return $this->isCount;
     }
 
+    public function isAggregate(): bool
+    {
+        return $this->isAggregate;
+    }
+
     public function withAccessCheck(): self
     {
         // The constructor of ObjectType is under backward compatibility promise.
@@ -35,6 +42,7 @@ public function withAccessCheck(): self
         );
         $type->hasAccessCheck = true;
         $type->isCount = $this->isCount;
+        $type->isAggregate = $this->isAggregate;
         return $type;
     }
 
@@ -48,6 +56,21 @@ public function asCount(): self
         );
         $type->hasAccessCheck = $this->hasAccessCheck;
         $type->isCount = true;
+        $type->isAggregate = $this->isAggregate;
+        return $type;
+    }
+
+    public function asAggregate(): self
+    {
+        // @phpstan-ignore new.static
+        $type = new static(
+            $this->getClassName(),
+            $this->getSubtractedType(),
+            $this->getClassReflection()
+        );
+        $type->hasAccessCheck = $this->hasAccessCheck;
+        $type->isCount = $this->isCount;
+        $type->isAggregate = true;
         return $type;
     }
 
@@ -55,7 +78,8 @@ protected function describeAdditionalCacheKey(): string
     {
         $parts = [
             $this->hasAccessCheck ? 'with-access-check' : 'without-access-check',
-            $this->isCount ? 'count' : ''
+            $this->isCount ? 'count' : '',
+            $this->isAggregate ? 'aggregate' : '',
         ];
         return implode('-', $parts);
     }
diff --git a/src/Type/EntityStorage/GetQueryReturnTypeExtension.php b/src/Type/EntityStorage/GetQueryReturnTypeExtension.php
index 62efb7d9..0b9de299 100644
--- a/src/Type/EntityStorage/GetQueryReturnTypeExtension.php
+++ b/src/Type/EntityStorage/GetQueryReturnTypeExtension.php
@@ -59,12 +59,19 @@ public function getTypeFromMethodCall(
             return $returnType;
         }
 
+        $isAggregate = $methodReflection->getName() === 'getAggregateQuery';
+
         if ((new ObjectType(ContentEntityStorageInterface::class))->isSuperTypeOf($callerType)->yes()) {
-            return new ContentEntityQueryType($className);
+            $queryType = new ContentEntityQueryType($className);
+            return $isAggregate ? $queryType->asAggregate() : $queryType;
         }
         if ((new ObjectType(ConfigEntityStorageInterface::class))->isSuperTypeOf($callerType)->yes()) {
+            // Core throws QueryException for an aggregate query over config
+            // entities, so there is no aggregate query type to produce here.
+            // @see \Drupal\Core\Config\Entity\Query\QueryFactory::getAggregate()
             return new ConfigEntityQueryType($className);
         }
-        return new EntityQueryType($className);
+        $queryType = new EntityQueryType($className);
+        return $isAggregate ? $queryType->asAggregate() : $queryType;
     }
 }
diff --git a/tests/src/Type/EntityQuery/EntityQueryDynamicReturnTypeExtensionTest.php b/tests/src/Type/EntityQuery/EntityQueryDynamicReturnTypeExtensionTest.php
index 8d2086c1..9cff14bf 100644
--- a/tests/src/Type/EntityQuery/EntityQueryDynamicReturnTypeExtensionTest.php
+++ b/tests/src/Type/EntityQuery/EntityQueryDynamicReturnTypeExtensionTest.php
@@ -14,6 +14,7 @@ final class EntityQueryDynamicReturnTypeExtensionTest extends TypeInferenceTestC
     public static function dataFileAsserts(): iterable
     {
         yield from self::gatherAssertTypes(__DIR__ . '/../data/entity-query-execute.php');
+        yield from self::gatherAssertTypes(__DIR__ . '/../data/aggregate-query-execute.php');
         yield from self::gatherAssertTypes(__DIR__ . '/../data/bug-355-entity-query.php');
         yield from self::gatherAssertTypes(__DIR__ . '/../data/bug-522.php');
         yield from self::gatherAssertTypes(__DIR__ . '/../data/bug-909.php');
diff --git a/tests/src/Type/data/aggregate-query-execute.php b/tests/src/Type/data/aggregate-query-execute.php
new file mode 100644
index 00000000..b8a008ed
--- /dev/null
+++ b/tests/src/Type/data/aggregate-query-execute.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DrupalAggregateQuery;
+
+use function PHPStan\Testing\assertType;
+
+// An aggregate query grouped by a field returns a list of result rows, where
+// each row is an array keyed by the aggregate results and the groupBy columns.
+// @see \Drupal\Core\Entity\Query\QueryAggregateInterface::execute()
+$rows = \Drupal::entityTypeManager()->getStorage('node')->getAggregateQuery()
+    ->accessCheck(FALSE)
+    ->condition('status', TRUE)
+    ->groupBy('type')
+    ->execute();
+assertType('array<int, array<string, string|null>>', $rows);
+
+// array_column() over those rows pulls a single groupBy column back out, which
+// is the pattern used to collect the grouped IDs for a follow-up query.
+$ids = array_column(
+    \Drupal::entityTypeManager()->getStorage('node')->getAggregateQuery()
+        ->accessCheck(FALSE)
+        ->condition('status', TRUE)
+        ->groupBy('type')
+        ->execute(),
+    'type'
+);
+assertType('list<string|null>', $ids);
+
+// Because the column can be present, the result is not statically empty, so a
+// truthiness check on it is meaningful rather than "always false".
+$filtered = $ids ? $ids : [];
+assertType('list<string|null>', $filtered);