diff --git a/docs/cli.rst b/docs/cli.rst
index addf7c6..49d5d92 100644
--- a/docs/cli.rst
+++ b/docs/cli.rst
@@ -230,7 +230,7 @@ You can add a column using the ``add-column`` command::
 
     $ sqlite-utils add-column mydb.db mytable nameofcolumn text
 
-The last argument here is the type of the column to be created. You can use one of ``text``, ``integer``, ``float`` or ``blob``.
+The last argument here is the type of the column to be created. You can use one of ``text``, ``integer``, ``float`` or ``blob``. If you leave it off, ``text`` will be used.
 
 .. _cli_add_foreign_key:
 
diff --git a/docs/python-api.rst b/docs/python-api.rst
index d3d05d3..8171629 100644
--- a/docs/python-api.rst
+++ b/docs/python-api.rst
@@ -232,9 +232,12 @@ You can add a new column to a table using the ``.add_column(col_name, col_type)`
     db["dogs"].add_column("weight", float)
     db["dogs"].add_column("dob", datetime.date)
     db["dogs"].add_column("image", "BLOB")
+    db["dogs"].add_column("website") # str by default
 
 You can specify the ``col_type`` argument either using a SQLite type as a string, or by directly passing a Python type e.g. ``str`` or ``float``.
 
+The ``col_type`` is optional - if you omit it the type of ``TEXT`` will be used.
+
 SQLite types you can specify are ``"TEXT"``, ``"INTEGER"``, ``"FLOAT"`` or ``"BLOB"``.
 
 If you pass a Python type, it will be mapped to SQLite types as shown here::
diff --git a/sqlite_utils/cli.py b/sqlite_utils/cli.py
index 665aa32..63fcffb 100644
--- a/sqlite_utils/cli.py
+++ b/sqlite_utils/cli.py
@@ -148,6 +148,7 @@ def optimize(path, no_vacuum):
     type=click.Choice(
         ["integer", "float", "blob", "text", "INTEGER", "FLOAT", "BLOB", "TEXT"]
     ),
+    required=False,
 )
 def add_column(path, table, col_name, col_type):
     "Add a column to the specified table"
diff --git a/sqlite_utils/db.py b/sqlite_utils/db.py
index 725ba53..9b9170f 100644
--- a/sqlite_utils/db.py
+++ b/sqlite_utils/db.py
@@ -276,7 +276,9 @@ class Table:
         self.db.conn.execute(sql)
         return self
 
-    def add_column(self, col_name, col_type):
+    def add_column(self, col_name, col_type=None):
+        if col_type is None:
+            col_type = str
         sql = "ALTER TABLE [{table}] ADD COLUMN [{col_name}] {col_type};".format(
             table=self.name, col_name=col_name, col_type=COLUMN_TYPE_MAPPING[col_type]
         )
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 7f2d17f..ad2bec7 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -183,6 +183,7 @@ def test_create_index(db_path):
         ),
         ("float", "FLOAT", "CREATE TABLE [dogs] ( [name] TEXT , [float] FLOAT)"),
         ("blob", "blob", "CREATE TABLE [dogs] ( [name] TEXT , [blob] BLOB)"),
+        ("default", None, "CREATE TABLE [dogs] ( [name] TEXT , [default] TEXT)"),
     ),
 )
 def test_add_column(db_path, col_name, col_type, expected_schema):
@@ -191,12 +192,10 @@ def test_add_column(db_path, col_name, col_type, expected_schema):
     assert "CREATE TABLE [dogs] ( [name] TEXT )" == collapse_whitespace(
         db["dogs"].schema
     )
-    assert (
-        0
-        == CliRunner()
-        .invoke(cli.cli, ["add-column", db_path, "dogs", col_name, col_type])
-        .exit_code
-    )
+    args = ["add-column", db_path, "dogs", col_name]
+    if col_type is not None:
+        args.append(col_type)
+    assert 0 == CliRunner().invoke(cli.cli, args).exit_code
     assert expected_schema == collapse_whitespace(db["dogs"].schema)
 
 
diff --git a/tests/test_create.py b/tests/test_create.py
index 7aaae5d..24f4e97 100644
--- a/tests/test_create.py
+++ b/tests/test_create.py
@@ -145,6 +145,11 @@ def test_create_error_if_invalid_foreign_keys(fresh_db):
         ),
         ("float", "FLOAT", "CREATE TABLE [dogs] ( [name] TEXT , [float] FLOAT)"),
         ("blob", "blob", "CREATE TABLE [dogs] ( [name] TEXT , [blob] BLOB)"),
+        (
+            "default_str",
+            None,
+            "CREATE TABLE [dogs] ( [name] TEXT , [default_str] TEXT)",
+        ),
     ),
 )
 def test_add_column(fresh_db, col_name, col_type, expected_schema):