diff --git a/model_clone/mixins/clone.py b/model_clone/mixins/clone.py
index 8ab09d13..d10306a7 100644
--- a/model_clone/mixins/clone.py
+++ b/model_clone/mixins/clone.py
@@ -325,7 +325,10 @@ def _create_copy_of_instance(instance, force=False, sub_clone=False):
                 ]
             ):
                 # Do not try to get unique value for enum type field
-                if isinstance(f, models.CharField) and not f.choices:
+                if (
+                    isinstance(f, (models.CharField, models.TextField))
+                    and not f.choices
+                ):
                     value = clean_value(value, unique_duplicate_suffix)
                     if use_unique_duplicate_suffix:
                         value = get_unique_value(
diff --git a/model_clone/tests/test_clone_mixin.py b/model_clone/tests/test_clone_mixin.py
index 4ce69ef1..c6bf3d51 100644
--- a/model_clone/tests/test_clone_mixin.py
+++ b/model_clone/tests/test_clone_mixin.py
@@ -25,6 +25,7 @@
     BookSaleTag,
     Tag,
     SaleTag,
+    Product,
 )
 
 User = get_user_model()
@@ -649,3 +650,11 @@ def test_cloning_multiple_instances_with_autocommit_is_valid(self):
                 clone.first_name,
                 r"{}\s[\d]".format(Author.UNIQUE_DUPLICATE_SUFFIX),
             )
+
+    def test_cloning_model_with_unique_text_field(self):
+        product = Product.objects.create(name="Test Product")
+        clone = product.make_clone()
+        self.assertEqual(
+            clone.name,
+            "{0} {1} 1".format(product.name, Product.UNIQUE_DUPLICATE_SUFFIX),
+        )
diff --git a/model_clone/utils.py b/model_clone/utils.py
index 0fad5476..64a1a855 100644
--- a/model_clone/utils.py
+++ b/model_clone/utils.py
@@ -162,7 +162,7 @@ def get_value(value, suffix, transform, max_length, index):
     duplicate_suffix = " {} {}".format(suffix, index)
     total_length = len(value + duplicate_suffix)
 
-    if total_length > max_length:
+    if max_length is not None and total_length > max_length:
         # Truncate the value to max_length - suffix length.
         value = value[: max_length - len(duplicate_suffix)]
 
diff --git a/sample/migrations/0016_product.py b/sample/migrations/0016_product.py
new file mode 100644
index 00000000..8d069263
--- /dev/null
+++ b/sample/migrations/0016_product.py
@@ -0,0 +1,28 @@
+# Generated by Django 3.2.3 on 2021-05-17 12:29
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("sample", "0015_auto_20210423_0935"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Product",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("name", models.TextField(unique=True)),
+            ],
+        ),
+    ]
diff --git a/sample/models.py b/sample/models.py
index 0e0b88e8..ebcdd3ae 100644
--- a/sample/models.py
+++ b/sample/models.py
@@ -235,3 +235,7 @@ class Cover(CloneModel):
 class BackCover(models.Model):
     content = models.CharField(max_length=200)
     book = models.OneToOneField(Book, on_delete=models.CASCADE)
+
+
+class Product(CloneMixin, models.Model):
+    name = models.TextField(unique=True)