diff --git a/includes/classes/Feature/Autosuggest/Autosuggest.php b/includes/classes/Feature/Autosuggest/Autosuggest.php
index 1b9eea9b9..d77f4cdbc 100644
--- a/includes/classes/Feature/Autosuggest/Autosuggest.php
+++ b/includes/classes/Feature/Autosuggest/Autosuggest.php
@@ -180,7 +180,7 @@ public function mapping( $mapping ) {
 	 * @return array
 	 */
 	public function set_fuzziness( $fuzziness, $search_fields, $args ) {
-		if ( Utils\is_integrated_request( $this->slug, [ 'public' ] ) && ! empty( $args['s'] ) ) {
+		if ( Utils\is_integrated_request( $this->slug, $this->get_contexts() ) && ! empty( $args['s'] ) ) {
 			return 'auto';
 		}
 		return $fuzziness;
@@ -195,7 +195,7 @@ public function set_fuzziness( $fuzziness, $search_fields, $args ) {
 	 * @return array $query adjusted ES Query arguments
 	 */
 	public function adjust_fuzzy_fields( $query, $post_type, $args ) {
-		if ( ! Utils\is_integrated_request( $this->slug, [ 'public' ] ) || empty( $args['s'] ) ) {
+		if ( ! Utils\is_integrated_request( $this->slug, $this->get_contexts() ) || empty( $args['s'] ) ) {
 			return $query;
 		}
 
@@ -926,4 +926,22 @@ public function delete_cached_query() {
 			'ElasticPress 4.7.0'
 		);
 	}
+
+	/**
+	 * Get the contexts for autosuggest.
+	 *
+	 * @since 5.1.0
+	 * @return array
+	 */
+	protected function get_contexts() : array {
+		/**
+		 * Filter contexts for autosuggest.
+		 *
+		 * @hook ep_autosuggest_contexts
+		 * @since 5.1.0
+		 * @param {array} $contexts Contexts for autosuggest
+		 * @return {array} New contexts
+		 */
+		return apply_filters( 'ep_autosuggest_contexts', [ 'public', 'ajax' ] );
+	}
 }
diff --git a/includes/utils.php b/includes/utils.php
index 1d6d5aa53..be0f5bc7d 100644
--- a/includes/utils.php
+++ b/includes/utils.php
@@ -675,7 +675,7 @@ function is_integrated_request( $context, $types = [] ) {
 	}
 
 	$is_admin_request             = is_admin();
-	$is_ajax_request              = defined( 'DOING_AJAX' ) && DOING_AJAX;
+	$is_ajax_request              = wp_doing_ajax();
 	$is_rest_request              = defined( 'REST_REQUEST' ) && REST_REQUEST;
 	$is_integrated_admin_request  = false;
 	$is_integrated_ajax_request   = false;
diff --git a/tests/php/features/TestAutosuggest.php b/tests/php/features/TestAutosuggest.php
index 796c821a2..d4bfa8b56 100644
--- a/tests/php/features/TestAutosuggest.php
+++ b/tests/php/features/TestAutosuggest.php
@@ -321,4 +321,200 @@ public function test_get_settings_schema() {
 			$settings_keys
 		);
 	}
+
+	/**
+	 * Test whether autosuggest ngram fields apply to the search query when AJAX integration and weighting is enabled.
+	 *
+	 * @since 5.1.0
+	 * @group autosuggest
+	 */
+	public function test_autosuggest_ngram_fields_for_ajax_request() {
+		add_filter( 'wp_doing_ajax', '__return_true' );
+		add_filter( 'ep_ajax_wp_query_integration', '__return_true' );
+		add_filter( 'ep_enable_do_weighting', '__return_true' );
+
+		$this->get_feature()->setup();
+
+		$this->ep_factory->post->create(
+			array(
+				'post_title' => 'search me',
+				'post_type'  => 'post',
+			)
+		);
+
+		ElasticPress\Elasticsearch::factory()->refresh_indices();
+
+		add_filter(
+			'ep_query_request_path',
+			function( $path, $index, $type, $query, $query_args, $query_object ) {
+				$fields = $query['query']['function_score']['query']['bool']['should'][0]['bool']['must'][0]['bool']['should'][1]['multi_match']['fields'];
+
+				$this->assertContains( 'term_suggest^1', $fields );
+				$this->assertContains( 'post_title.suggest^1', $fields );
+				return $path;
+			},
+			10,
+			6
+		);
+
+		$query = new \WP_Query(
+			array(
+				's'            => 'search me',
+				'ep_integrate' => true,
+			)
+		);
+
+		$this->assertTrue( $query->elasticsearch_success );
+		$this->assertEquals( 1, $query->found_posts );
+	}
+
+	/**
+	 * Test whether autosuggest ngram fields do not apply to the search query when `ep_autosuggest_contexts` is only set to public.
+	 *
+	 * @since 5.1.0
+	 * @group autosuggest
+	 */
+	public function test_autosuggest_ngram_fields_for_ajax_request_negative() {
+		add_filter( 'wp_doing_ajax', '__return_true' );
+		add_filter( 'ep_ajax_wp_query_integration', '__return_true' );
+		add_filter( 'ep_enable_do_weighting', '__return_true' );
+
+		$autosuggest_context = function() {
+			return [ 'public' ];
+		};
+
+		add_filter( 'ep_autosuggest_contexts', $autosuggest_context );
+
+		$this->get_feature()->setup();
+
+		$this->ep_factory->post->create(
+			array(
+				'post_title' => 'search me',
+				'post_type'  => 'post',
+			)
+		);
+
+		ElasticPress\Elasticsearch::factory()->refresh_indices();
+
+		add_filter(
+			'ep_query_request_path',
+			function( $path, $index, $type, $query, $query_args, $query_object ) {
+				$fields = $query['query']['function_score']['query']['bool']['should'][0]['bool']['must'][0]['bool']['should'][1]['multi_match']['fields'];
+
+				$this->assertNotContains( 'term_suggest^1', $fields );
+				$this->assertNotContains( 'post_title.suggest^1', $fields );
+				return $path;
+			},
+			10,
+			6
+		);
+
+		$query = new \WP_Query(
+			array(
+				's'            => 'search me',
+				'ep_integrate' => true,
+			)
+		);
+
+		$this->assertTrue( $query->elasticsearch_success );
+		$this->assertEquals( 1, $query->found_posts );
+	}
+
+	/**
+	 * Test whether fuzziness is set to `auto` for AJAX calls.
+	 *
+	 * @since 5.1.0
+	 * @group autosuggest
+	 */
+	public function test_fuziness_with_type_auto_set_for_ajax_call() {
+		add_filter( 'wp_doing_ajax', '__return_true' );
+		add_filter( 'ep_ajax_wp_query_integration', '__return_true' );
+
+		$algorithm = function() {
+			return 'default';
+		};
+		add_filter( 'ep_search_algorithm_version', $algorithm );
+
+		$this->get_feature()->setup();
+
+		$this->ep_factory->post->create(
+			array(
+				'post_title' => 'search me',
+				'post_type'  => 'post',
+			)
+		);
+
+		ElasticPress\Elasticsearch::factory()->refresh_indices();
+
+		add_filter(
+			'ep_query_request_path',
+			function( $path, $index, $type, $query, $query_args, $query_object ) {
+				$this->assertEquals( 'auto', $query['query']['function_score']['query']['bool']['should'][2]['multi_match']['fuzziness'] );
+				return $path;
+			},
+			10,
+			6
+		);
+
+		$query = new \WP_Query(
+			array(
+				's'            => 'search me',
+				'ep_integrate' => true,
+			)
+		);
+
+		$this->assertTrue( $query->elasticsearch_success );
+	}
+
+	/**
+	 * Test whether fuzziness is not set to `auto` for AJAX calls when `ep_autosuggest_contexts` is only set to public.
+	 *
+	 * @since 5.1.0
+	 * @group autosuggest
+	 */
+	public function test_fuziness_with_type_auto_set_for_ajax_call_negative() {
+		add_filter( 'wp_doing_ajax', '__return_true' );
+		add_filter( 'ep_ajax_wp_query_integration', '__return_true' );
+
+		$algorithm = function() {
+			return 'default';
+		};
+		add_filter( 'ep_search_algorithm_version', $algorithm );
+
+		$autosuggest_context = function() {
+			return [ 'public' ];
+		};
+		add_filter( 'ep_autosuggest_contexts', $autosuggest_context );
+
+		$this->get_feature()->setup();
+
+		$this->ep_factory->post->create(
+			array(
+				'post_title' => 'search me',
+				'post_type'  => 'post',
+			)
+		);
+
+		ElasticPress\Elasticsearch::factory()->refresh_indices();
+
+		add_filter(
+			'ep_query_request_path',
+			function( $path, $index, $type, $query, $query_args, $query_object ) {
+				$this->assertNotEquals( 'auto', $query['query']['function_score']['query']['bool']['should'][2]['multi_match']['fuzziness'] );
+				return $path;
+			},
+			10,
+			6
+		);
+
+		$query = new \WP_Query(
+			array(
+				's'            => 'search me',
+				'ep_integrate' => true,
+			)
+		);
+
+		$this->assertTrue( $query->elasticsearch_success );
+
+	}
 }