diff --git a/src/Platforms/SQLServerPlatform.php b/src/Platforms/SQLServerPlatform.php
index a4e81c6e5e4..ac5cf8eba90 100644
--- a/src/Platforms/SQLServerPlatform.php
+++ b/src/Platforms/SQLServerPlatform.php
@@ -1306,7 +1306,7 @@ public function getAsciiStringTypeDeclarationSQL(array $column): string
     {
         $length = $column['length'] ?? null;
 
-        if (! isset($column['fixed'])) {
+        if (empty($column['fixed'])) {
             return sprintf('VARCHAR(%d)', $length ?? 255);
         }
 
diff --git a/tests/Platforms/SQLServerPlatformTest.php b/tests/Platforms/SQLServerPlatformTest.php
index 4cb48bc59ab..b9e5dadf1ec 100644
--- a/tests/Platforms/SQLServerPlatformTest.php
+++ b/tests/Platforms/SQLServerPlatformTest.php
@@ -123,10 +123,20 @@ public function testGeneratesTypeDeclarationsForStrings(): void
             'NVARCHAR(50)',
             $this->platform->getStringTypeDeclarationSQL(['length' => 50]),
         );
+        self::assertEquals(
+            'NVARCHAR(50)',
+            $this->platform->getStringTypeDeclarationSQL(
+                ['length' => 50, 'fixed' => false],
+            ),
+        );
         self::assertEquals(
             'NVARCHAR(255)',
             $this->platform->getStringTypeDeclarationSQL([]),
         );
+        self::assertEquals(
+            'NVARCHAR(255)',
+            $this->platform->getStringTypeDeclarationSQL(['fixed' => false]),
+        );
         self::assertSame('VARCHAR(MAX)', $this->platform->getClobTypeDeclarationSQL([]));
         self::assertSame(
             'VARCHAR(MAX)',
@@ -134,6 +144,34 @@ public function testGeneratesTypeDeclarationsForStrings(): void
         );
     }
 
+    public function testGeneratesTypeDeclarationsForAsciiStrings(): void
+    {
+        self::assertEquals(
+            'CHAR(10)',
+            $this->platform->getAsciiStringTypeDeclarationSQL(
+                ['length' => 10, 'fixed' => true],
+            ),
+        );
+        self::assertEquals(
+            'VARCHAR(50)',
+            $this->platform->getAsciiStringTypeDeclarationSQL(['length' => 50]),
+        );
+        self::assertEquals(
+            'VARCHAR(50)',
+            $this->platform->getAsciiStringTypeDeclarationSQL(
+                ['length' => 50, 'fixed' => false],
+            ),
+        );
+        self::assertEquals(
+            'VARCHAR(255)',
+            $this->platform->getAsciiStringTypeDeclarationSQL([]),
+        );
+        self::assertEquals(
+            'VARCHAR(255)',
+            $this->platform->getAsciiStringTypeDeclarationSQL(['fixed' => false]),
+        );
+    }
+
     public function testPrefersIdentityColumns(): void
     {
         self::assertTrue($this->platform->prefersIdentityColumns());