diff --git a/.github/setup-sphinx.sh b/.github/setup-sphinx.sh
new file mode 100755
index 0000000000..919d142575
--- /dev/null
+++ b/.github/setup-sphinx.sh
@@ -0,0 +1,144 @@
+#!/bin/bash
+#
+# This file is part of the phpBB Forum Software package.
+#
+# @copyright (c) phpBB Limited <https://www.phpbb.com>
+# @license GNU General Public License, version 2 (GPL-2.0)
+#
+# For full copyright and license information, please see
+# the docs/CREDITS.txt file.
+#
+set -e
+set -x
+
+sudo apt-get update
+sudo apt-get install -q -y sphinxsearch
+
+DIR=$(dirname "$0")
+
+SPHINX_DAEMON_HOST="localhost"
+SPHINX_DAEMON_PORT="9312"
+SPHINX_CONF="$DIR/sphinx.conf"
+SPHINX_DATA_DIR="/var/run/sphinxsearch"
+SPHINX_LOG="$SPHINX_DATA_DIR/log/searchd.log"
+SPHINX_QUERY_LOG="$SPHINX_DATA_DIR/log/sphinx-query.log"
+ID="saw9zf2fdhp1goue" # Randomly generated via phpBB unique_id()
+
+PHPBB_TEST_DBHOST="0.0.0.0"
+PHPBB_TEST_DBNAME="phpbb_tests"
+PHPBB_TEST_DBUSER="root"
+PHPBB_TEST_DBPASSWD=""
+
+sudo service sphinxsearch stop
+sudo mkdir -p "$SPHINX_DATA_DIR/log"
+sudo chown "sphinxsearch" "$SPHINX_DATA_DIR/log"
+
+# Generate configuration file for Sphinx
+echo "
+source source_phpbb_${ID}_main 
+{
+	type = mysql # mysql or pgsql
+	sql_host =  $PHPBB_TEST_DBHOST
+	sql_user = $PHPBB_TEST_DBUSER
+	sql_pass = $PHPBB_TEST_DBPASSWD
+	sql_db = $PHPBB_TEST_DBNAME
+	sql_port =
+	sql_query_pre = SET NAMES 'utf8'
+	sql_query_pre = UPDATE phpbb_sphinx SET max_doc_id = (SELECT MAX(post_id) FROM phpbb_posts) WHERE counter_id = 1
+	sql_query_range = SELECT MIN(post_id), MAX(post_id) FROM phpbb_posts
+	sql_range_step = 5000
+	sql_query = SELECT \
+						p.post_id AS id, \
+						p.forum_id, \
+						p.topic_id, \
+						p.poster_id, \
+						p.post_visibility, \
+						CASE WHEN p.post_id = t.topic_first_post_id THEN 1 ELSE 0 END as topic_first_post, \
+						p.post_time, \
+						p.post_subject, \
+						p.post_subject as title, \
+						p.post_text as data, \
+						t.topic_last_post_time, \
+						0 as deleted \
+					FROM phpbb_posts p, phpbb_topics t \
+					WHERE \
+						p.topic_id = t.topic_id \
+						AND p.post_id >= \$start AND p.post_id <= \$end
+	sql_query_post =
+	sql_query_post_index = UPDATE phpbb_sphinx SET max_doc_id = \$maxid WHERE counter_id = 1
+	sql_attr_uint = forum_id
+	sql_attr_uint = topic_id
+	sql_attr_uint = poster_id
+	sql_attr_uint = post_visibility
+	sql_attr_bool = topic_first_post
+	sql_attr_bool = deleted
+	sql_attr_timestamp = post_time
+	sql_attr_timestamp = topic_last_post_time
+	sql_attr_string = post_subject
+}
+source source_phpbb_${ID}_delta : source_phpbb_${ID}_main
+{
+	sql_query_pre = SET NAMES 'utf8'
+	sql_query_range =
+	sql_range_step =
+	sql_query = SELECT \
+						p.post_id AS id, \
+						p.forum_id, \
+						p.topic_id, \
+						p.poster_id, \
+						p.post_visibility, \
+						CASE WHEN p.post_id = t.topic_first_post_id THEN 1 ELSE 0 END as topic_first_post, \
+						p.post_time, \
+						p.post_subject, \
+						p.post_subject as title, \
+						p.post_text as data, \
+						t.topic_last_post_time, \
+						0 as deleted \
+					FROM phpbb_posts p, phpbb_topics t \
+					WHERE \
+						p.topic_id = t.topic_id \
+						AND p.post_id >=  ( SELECT max_doc_id FROM phpbb_sphinx WHERE counter_id=1 )
+	sql_query_post_index =
+}
+index index_phpbb_${ID}_main
+{
+	path = $SPHINX_DATA_DIR/index_phpbb_${ID}_main
+	source = source_phpbb_${ID}_main
+	docinfo = extern
+	morphology = none
+	stopwords =
+	wordforms =
+	exceptions =
+	min_word_len = 2
+	charset_table = U+FF10..U+FF19->0..9, 0..9, U+FF41..U+FF5A->a..z, U+FF21..U+FF3A->a..z, A..Z->a..z, a..z, U+0149, U+017F, U+0138, U+00DF, U+00FF, U+00C0..U+00D6->U+00E0..U+00F6, U+00E0..U+00F6, U+00D8..U+00DE->U+00F8..U+00FE, U+00F8..U+00FE, U+0100->U+0101, U+0101, U+0102->U+0103, U+0103, U+0104->U+0105, U+0105, U+0106->U+0107, U+0107, U+0108->U+0109, U+0109, U+010A->U+010B, U+010B, U+010C->U+010D, U+010D, U+010E->U+010F, U+010F, U+0110->U+0111, U+0111, U+0112->U+0113, U+0113, U+0114->U+0115, U+0115, U+0116->U+0117, U+0117, U+0118->U+0119, U+0119, U+011A->U+011B, U+011B, U+011C->U+011D, U+011D, U+011E->U+011F, U+011F, U+0130->U+0131, U+0131, U+0132->U+0133, U+0133, U+0134->U+0135, U+0135, U+0136->U+0137, U+0137, U+0139->U+013A, U+013A, U+013B->U+013C, U+013C, U+013D->U+013E, U+013E, U+013F->U+0140, U+0140, U+0141->U+0142, U+0142, U+0143->U+0144, U+0144, U+0145->U+0146, U+0146, U+0147->U+0148, U+0148, U+014A->U+014B, U+014B, U+014C->U+014D, U+014D, U+014E->U+014F, U+014F, U+0150->U+0151, U+0151, U+0152->U+0153, U+0153, U+0154->U+0155, U+0155, U+0156->U+0157, U+0157, U+0158->U+0159, U+0159, U+015A->U+015B, U+015B, U+015C->U+015D, U+015D, U+015E->U+015F, U+015F, U+0160->U+0161, U+0161, U+0162->U+0163, U+0163, U+0164->U+0165, U+0165, U+0166->U+0167, U+0167, U+0168->U+0169, U+0169, U+016A->U+016B, U+016B, U+016C->U+016D, U+016D, U+016E->U+016F, U+016F, U+0170->U+0171, U+0171, U+0172->U+0173, U+0173, U+0174->U+0175, U+0175, U+0176->U+0177, U+0177, U+0178->U+00FF, U+00FF, U+0179->U+017A, U+017A, U+017B->U+017C, U+017C, U+017D->U+017E, U+017E, U+0410..U+042F->U+0430..U+044F, U+0430..U+044F, U+4E00..U+9FFF
+	ignore_chars = U+0027, U+002C
+	min_prefix_len = 3
+	min_infix_len = 0
+	html_strip = 1
+	index_exact_words = 0
+	blend_chars = U+23, U+24, U+25, U+26, U+40
+}
+index index_phpbb_${ID}_delta : index_phpbb_${ID}_main
+{
+	path = $SPHINX_DATA_DIR/index_phpbb_${ID}_delta
+	source = source_phpbb_${ID}_delta
+}
+indexer
+{
+	mem_limit = 512M
+}
+searchd
+{
+	listen = $SPHINX_DAEMON_PORT
+	log = $SPHINX_LOG
+	query_log = $SPHINX_QUERY_LOG
+	read_timeout = 5
+	max_children = 30
+	pid_file = $SPHINX_DATA_DIR/searchd.pid
+	binlog_path = $SPHINX_DATA_DIR/
+}
+" > $SPHINX_CONF
+
+sudo mv "$SPHINX_CONF" "/etc/sphinxsearch/sphinx.conf"
+sudo sed -i "s/START=no/START=yes/g" "/etc/default/sphinxsearch"
+sudo chmod 777 "/var/run/sphinxsearch"
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 1cdd4ab533..2fdbaba80b 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -213,6 +213,10 @@ jobs:
               run: |
                   .github/setup-ldap.sh
 
+            - name: Setup SPHINX
+              run: |
+                  .github/setup-sphinx.sh
+
             - name: Lint tests
               if: ${{ matrix.SLOWTESTS != 1 && steps.database-type.outputs.db == 'mysql' }}
               run: phpBB/vendor/bin/phpunit tests/lint_test.php
diff --git a/phpBB/phpbb/search/backend/fulltext_sphinx.php b/phpBB/phpbb/search/backend/fulltext_sphinx.php
index e32ccfaea5..842aacee96 100644
--- a/phpBB/phpbb/search/backend/fulltext_sphinx.php
+++ b/phpBB/phpbb/search/backend/fulltext_sphinx.php
@@ -631,7 +631,7 @@ class fulltext_sphinx implements search_backend_interface
 	 */
 	public function create_index(int &$post_counter = 0): ?array
 	{
-		if ($this->index_created())
+		if (!$this->index_created())
 		{
 			$table_data = array(
 				'COLUMNS'	=> array(
diff --git a/tests/functional/search/base.php b/tests/functional/search/base.php
index 885cd9c684..5d36b48bdd 100644
--- a/tests/functional/search/base.php
+++ b/tests/functional/search/base.php
@@ -50,6 +50,12 @@ abstract class phpbb_functional_search_base extends phpbb_functional_test_case
 		{
 			$values["config[search_type]"] = $this->search_backend;
 
+			if (strpos($this->search_backend, 'fulltext_sphinx'))
+			{
+				// Set board Sphinx id in according to respective setup-sphinx.sh $ID value
+				$values["config[fulltext_sphinx_id]"] = 'saw9zf2fdhp1goue';
+			}
+
 			try
 			{
 				$form->setValues($values);
@@ -62,6 +68,7 @@ abstract class phpbb_functional_search_base extends phpbb_functional_test_case
 			}
 
 			$crawler = self::submit($form);
+			$this->purge_cache();
 
 			$form = $crawler->selectButton('Yes')->form();
 			$values = $form->getValues();
diff --git a/tests/functional/search/sphinx_test.php b/tests/functional/search/sphinx_test.php
index 6e42da0e86..eaba34d17a 100644
--- a/tests/functional/search/sphinx_test.php
+++ b/tests/functional/search/sphinx_test.php
@@ -20,8 +20,29 @@ class phpbb_functional_search_sphinx_test extends phpbb_functional_search_base
 {
 	protected $search_backend = 'phpbb\search\backend\fulltext_sphinx';
 
+	protected function create_search_index($backend = null)
+	{
+		parent::create_search_index($backend);
+		$this->purge_cache();
+
+		if (!$backend || $this->search_backend == $backend)
+		{
+			// After creating phpBB search index, build Sphinx index
+			exec('sudo -S service sphinxsearch stop', $output, $retval); // Attemtp to stop sphinxsearch service in case it's running
+			exec('sudo -S indexer --all', $output, $retval); // Run sphinxsearch indexer
+			exec('sudo -S service sphinxsearch start', $output, $retval); // Attempt to start sphinxsearch service again
+		}
+	}
+
 	public function test_search_backend()
 	{
-		$this->markTestIncomplete('Sphinx Tests are not supported');
+		if ($this->db->sql_layer != 'mysqli') // Sphinx test runs on MySQL/MariaDB only so far
+		{
+			$this->markTestIncomplete('Sphinx Tests are not supported');
+		}
+		else
+		{
+			parent::test_search_backend();
+		}
 	}
 }