diff --git a/UPGRADE.md b/UPGRADE.md
index da8e9c863..0c7f7fc43 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -93,9 +93,10 @@ and the following changes were made:
 ### New classes with constants
 
 - `Yiisoft\Db\Constant\PhpType` with PHP types constants;
-- `Yiisoft\Db\Constant\GettypeResult` with `gettype()` function results constants.
-- `Yiisoft\Db\Constant\ColumnType` with abstract column types constants.
-- `Yiisoft\Db\Constant\PseudoType` with column pseudo-types constants.
+- `Yiisoft\Db\Constant\GettypeResult` with `gettype()` function results constants;
+- `Yiisoft\Db\Constant\ColumnType` with abstract column types constants;
+- `Yiisoft\Db\Constant\PseudoType` with column pseudo-types constants;
+- `Yiisoft\Db\Constant\IndexType` with table index types.
 
 ### New classes for table columns
 
diff --git a/src/Command/CommandInterface.php b/src/Command/CommandInterface.php
index 975cb9abf..a660f206f 100644
--- a/src/Command/CommandInterface.php
+++ b/src/Command/CommandInterface.php
@@ -9,6 +9,7 @@
 use Throwable;
 use Yiisoft\Db\Connection\ConnectionInterface;
 use Yiisoft\Db\Constant\ColumnType;
+use Yiisoft\Db\Constant\IndexType;
 use Yiisoft\Db\Constant\PseudoType;
 use Yiisoft\Db\Exception\Exception;
 use Yiisoft\Db\Exception\InvalidArgumentException;
@@ -296,13 +297,15 @@ public function checkIntegrity(string $schema, string $table, bool $check = true
      * @param string $name The name of the index.
      * @param array|string $columns The column(s) to include in the index. If there are many columns,
      * separate them with commas.
-     * @param string|null $indexType The type of index-supported DBMS - for example: `UNIQUE`, `FULLTEXT`, `SPATIAL`,
-     * `BITMAP` or null as default.
-     * @param string|null $indexMethod The setting index organization method (with `USING`, not all DBMS).
+     * @param string|null $indexType The type of the index supported by DBMS {@see IndexType} - for example: `UNIQUE`,
+     * `FULLTEXT`, `SPATIAL`, `BITMAP` or null as default.
+     * @param string|null $indexMethod The index organization method (with `USING`, not all DBMS).
      *
      * @throws Exception
      * @throws InvalidArgumentException
      *
+     * @psalm-param IndexType::*|null $indexType
+     *
      * Note: The method will quote the `name`, `table`, and `column` parameters before using them in the generated SQL.
      */
     public function createIndex(
diff --git a/src/Constant/IndexType.php b/src/Constant/IndexType.php
new file mode 100644
index 000000000..a87844d1e
--- /dev/null
+++ b/src/Constant/IndexType.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Db\Constant;
+
+/**
+ * Defines the available index types. It is used in {@see DDLQueryBuilderInterface::createIndex()}.
+ */
+final class IndexType
+{
+    /**
+     * Define the type of the index as `UNIQUE`.
+     *
+     * Supported by `MySQL`, `MariaDB`, `MSSQL`, `Oracle`, `PostgreSQL`, `SQLite`.
+     */
+    public const UNIQUE = 'UNIQUE';
+    /**
+     * Define the type of the index as `BTREE`.
+     *
+     * Supported by `MySQL`, `PostgreSQL`.
+     */
+    public const BTREE = 'BTREE';
+    /**
+     * Define the type of the index as `HASH`.
+     *
+     * Supported by `MySQL`, `PostgreSQL`.
+     */
+    public const HASH = 'HASH';
+    /**
+     * Define the type of the index as `FULLTEXT`.
+     *
+     * Supported by `MySQL`.
+     */
+    public const FULLTEXT = 'FULLTEXT';
+    /**
+     * Define the type of the index as `SPATIAL`.
+     *
+     * Supported by `MySQL`.
+     */
+    public const SPATIAL = 'SPATIAL';
+    /**
+     * Define the type of the index as `GIST`.
+     *
+     * Supported by `PostgreSQL`.
+     */
+    public const GIST = 'GIST';
+    /**
+     * Define the type of the index as `GIN`.
+     *
+     * Supported by `PostgreSQL`.
+     */
+    public const GIN = 'GIN';
+    /**
+     * Define the type of the index as `BRIN`.
+     *
+     * Supported by `PostgreSQL`.
+     */
+    public const BRIN = 'BRIN';
+    /**
+     * Define the type of the index as `CLUSTERED`.
+     *
+     * Supported by `MSSQL`.
+     */
+    public const CLUSTERED = 'CLUSTERED';
+    /**
+     * Define the type of the index as `NONCLUSTERED`.
+     *
+     * Supported by `MSSQL`.
+     */
+    public const NONCLUSTERED = 'NONCLUSTERED';
+    /**
+     * Define the type of the index as `BITMAP`.
+     *
+     * Supported by `Oracle`.
+     */
+    public const BITMAP = 'BITMAP';
+}
diff --git a/src/QueryBuilder/DDLQueryBuilderInterface.php b/src/QueryBuilder/DDLQueryBuilderInterface.php
index 00b474262..fa0043090 100644
--- a/src/QueryBuilder/DDLQueryBuilderInterface.php
+++ b/src/QueryBuilder/DDLQueryBuilderInterface.php
@@ -4,6 +4,7 @@
 
 namespace Yiisoft\Db\QueryBuilder;
 
+use Yiisoft\Db\Constant\IndexType;
 use Yiisoft\Db\Exception\Exception;
 use Yiisoft\Db\Exception\InvalidArgumentException;
 use Yiisoft\Db\Exception\InvalidConfigException;
@@ -204,15 +205,17 @@ public function checkIntegrity(string $schema = '', string $table = '', bool $ch
      * @param string $name The name of the index.
      * @param array|string $columns The column(s) to include in the index.
      * If there are many columns, separate them with commas or use an array to represent them.
-     * @param string|null $indexType Type of index-supported DBMS - for example, `UNIQUE`, `FULLTEXT`, `SPATIAL`, `BITMAP` or
-     * `null` as default
-     * @param string|null $indexMethod For setting index organization method (with `USING`, not all DBMS)
+     * @param string|null $indexType The type of the index supported by DBMS {@see IndexType} - for example, `UNIQUE`,
+     * `FULLTEXT`, `SPATIAL`, `BITMAP` or `null` as default.
+     * @param string|null $indexMethod The index organization method (with `USING`, not all DBMS).
      *
      * @throws Exception
      * @throws InvalidArgumentException
      *
      * @return string The SQL statement for creating a new index.
      *
+     * @psalm-param IndexType::*|null $indexType
+     *
      * Note: The method will quote the `name`, `table`, and `column` parameters before using them in the generated SQL.
      */
     public function createIndex(
diff --git a/src/Schema/SchemaInterface.php b/src/Schema/SchemaInterface.php
index bddc3061f..1bdc58484 100644
--- a/src/Schema/SchemaInterface.php
+++ b/src/Schema/SchemaInterface.php
@@ -58,66 +58,88 @@ interface SchemaInterface extends ConstraintSchemaInterface
      * Define the type of the index as `UNIQUE`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `MySQL`, `MariaDB`, `MSSQL`, `Oracle`, `PostgreSQL`, `SQLite`.
+     *
+     * @deprecated Use {@see IndexType::UNIQUE} instead. Will be removed in 2.0.
      */
     public const INDEX_UNIQUE = 'UNIQUE';
     /**
      * Define the type of the index as `BTREE`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `MySQL`, `PostgreSQL`.
+     *
+     * @deprecated Use {@see IndexType::BTREE} instead. Will be removed in 2.0.
      */
     public const INDEX_BTREE = 'BTREE';
     /**
      * Define the type of the index as `HASH`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `MySQL`, `PostgreSQL`.
+     *
+     * @deprecated Use {@see IndexType::HASH} instead. Will be removed in 2.0.
      */
     public const INDEX_HASH = 'HASH';
     /**
      * Define the type of the index as `FULLTEXT`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `MySQL`.
+     *
+     * @deprecated Use {@see IndexType::FULLTEXT} instead. Will be removed in 2.0.
      */
     public const INDEX_FULLTEXT = 'FULLTEXT';
     /**
      * Define the type of the index as `SPATIAL`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `MySQL`.
+     *
+     * @deprecated Use {@see IndexType::SPATIAL} instead. Will be removed in 2.0.
      */
     public const INDEX_SPATIAL = 'SPATIAL';
     /**
      * Define the type of the index as `GIST`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `PostgreSQL`.
+     *
+     * @deprecated Use {@see IndexType::GIST} instead. Will be removed in 2.0.
      */
     public const INDEX_GIST = 'GIST';
     /**
      * Define the type of the index as `GIN`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `PostgreSQL`.
+     *
+     * @deprecated Use {@see IndexType::GIN} instead. Will be removed in 2.0.
      */
     public const INDEX_GIN = 'GIN';
     /**
      * Define the type of the index as `BRIN`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `PostgreSQL`.
+     *
+     * @deprecated Use {@see IndexType::BRIN} instead. Will be removed in 2.0.
      */
     public const INDEX_BRIN = 'BRIN';
     /**
      * Define the type of the index as `CLUSTERED`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `MSSQL`.
+     *
+     * @deprecated Use {@see IndexType::CLUSTERED} instead. Will be removed in 2.0.
      */
     public const INDEX_CLUSTERED = 'CLUSTERED';
     /**
      * Define the type of the index as `NONCLUSTERED`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `MSSQL`.
+     *
+     * @deprecated Use {@see IndexType::NONCLUSTERED} instead. Will be removed in 2.0.
      */
     public const INDEX_NONCLUSTERED = 'NONCLUSTERED';
     /**
      * Define the type of the index as `BITMAP`, it's used in {@see DDLQueryBuilderInterface::createIndex()}.
      *
      * Supported by `Oracle`.
+     *
+     * @deprecated Use {@see IndexType::BITMAP} instead. Will be removed in 2.0.
      */
     public const INDEX_BITMAP = 'BITMAP';
     /**
diff --git a/tests/Common/CommonSchemaTest.php b/tests/Common/CommonSchemaTest.php
index ac58fed79..23a01f330 100644
--- a/tests/Common/CommonSchemaTest.php
+++ b/tests/Common/CommonSchemaTest.php
@@ -9,6 +9,7 @@
 use Throwable;
 use Yiisoft\Db\Connection\ConnectionInterface;
 use Yiisoft\Db\Constant\ColumnType;
+use Yiisoft\Db\Constant\IndexType;
 use Yiisoft\Db\Constraint\CheckConstraint;
 use Yiisoft\Db\Constraint\Constraint;
 use Yiisoft\Db\Constraint\DefaultValueConstraint;
@@ -147,7 +148,7 @@ public function testFindUniquesIndexes(): void
             'uniqueIndex',
             'somecolUnique',
             'somecol',
-            SchemaInterface::INDEX_UNIQUE,
+            IndexType::UNIQUE,
         )->execute();
         $tableSchema = $schema->getTableSchema('uniqueIndex', true);
 
@@ -166,7 +167,7 @@ public function testFindUniquesIndexes(): void
             'uniqueIndex',
             'someCol2Unique',
             'someCol2',
-            SchemaInterface::INDEX_UNIQUE,
+            IndexType::UNIQUE,
         )->execute();
         $tableSchema = $schema->getTableSchema('uniqueIndex', true);
 
@@ -181,7 +182,7 @@ public function testFindUniquesIndexes(): void
             'uniqueIndex',
             'another unique index',
             'someCol3',
-            SchemaInterface::INDEX_UNIQUE,
+            IndexType::UNIQUE,
         )->execute();
         $tableSchema = $schema->getTableSchema('uniqueIndex', true);
 
diff --git a/tests/Provider/CommandProvider.php b/tests/Provider/CommandProvider.php
index ef542e013..d6d4f3173 100644
--- a/tests/Provider/CommandProvider.php
+++ b/tests/Provider/CommandProvider.php
@@ -10,6 +10,7 @@
 use Yiisoft\Db\Command\DataType;
 use Yiisoft\Db\Command\Param;
 use Yiisoft\Db\Constant\ColumnType;
+use Yiisoft\Db\Constant\IndexType;
 use Yiisoft\Db\Expression\Expression;
 use Yiisoft\Db\Query\Query;
 use Yiisoft\Db\Schema\Column\ColumnBuilder;
@@ -512,7 +513,7 @@ public static function createIndex(): array
     {
         return [
             ['{{test_idx_constraint_1}}', '{{test_idx}}', 'int1', null, null],
-            ['{{test_idx_constraint_2}}', '{{test_idx}}', ['int1'], SchemaInterface::INDEX_UNIQUE, null],
+            ['{{test_idx_constraint_2}}', '{{test_idx}}', ['int1'], IndexType::UNIQUE, null],
             ['{{test_idx_constraint_3}}', '{{test_idx}}', ['int1', 'int2'], null, null],
         ];
     }
@@ -550,7 +551,7 @@ public static function createIndexSql(): array
                 '{{name}}',
                 '{{table}}',
                 ['column1', 'column2'],
-                SchemaInterface::INDEX_UNIQUE,
+                IndexType::UNIQUE,
                 '',
                 DbHelper::replaceQuotes(
                     <<<SQL
diff --git a/tests/Provider/QueryBuilderProvider.php b/tests/Provider/QueryBuilderProvider.php
index bd7afa51c..bbc26e4b7 100644
--- a/tests/Provider/QueryBuilderProvider.php
+++ b/tests/Provider/QueryBuilderProvider.php
@@ -8,6 +8,7 @@
 use Yiisoft\Db\Command\DataType;
 use Yiisoft\Db\Command\Param;
 use Yiisoft\Db\Constant\ColumnType;
+use Yiisoft\Db\Constant\IndexType;
 use Yiisoft\Db\Constant\PseudoType;
 use Yiisoft\Db\Constraint\ForeignKeyConstraint;
 use Yiisoft\Db\Expression\Expression;
@@ -936,7 +937,7 @@ public static function createIndex(): array
                     $tableName,
                     $name1,
                     'C_index_1',
-                    SchemaInterface::INDEX_UNIQUE,
+                    IndexType::UNIQUE,
                 ),
             ],
             'create unique (2 columns)' => [
@@ -947,7 +948,7 @@ public static function createIndex(): array
                     $tableName,
                     $name2,
                     'C_index_2_1, C_index_2_2',
-                    SchemaInterface::INDEX_UNIQUE,
+                    IndexType::UNIQUE,
                 ),
             ],
         ];
diff --git a/tests/Provider/SchemaProvider.php b/tests/Provider/SchemaProvider.php
index bd451a4d1..fe840547d 100644
--- a/tests/Provider/SchemaProvider.php
+++ b/tests/Provider/SchemaProvider.php
@@ -5,6 +5,7 @@
 namespace Yiisoft\Db\Tests\Provider;
 
 use PDO;
+use Yiisoft\Db\Constant\IndexType;
 use Yiisoft\Db\Constraint\CheckConstraint;
 use Yiisoft\Db\Constraint\Constraint;
 use Yiisoft\Db\Constraint\ForeignKeyConstraint;
@@ -190,7 +191,7 @@ public static function withIndexDataProvider(): array
     {
         return [
             [
-                'indexType' => SchemaInterface::INDEX_UNIQUE,
+                'indexType' => IndexType::UNIQUE,
                 'indexMethod' => null,
                 'columnType' => null,
                 'isPrimary' => false,