diff --git a/sqlite_utils/db.py b/sqlite_utils/db.py
index 4f2b906..d40951e 100644
--- a/sqlite_utils/db.py
+++ b/sqlite_utils/db.py
@@ -410,6 +410,13 @@ class Table:
         elif len(pks) > 1:
             pk_names = pks
             last_pk = pk_values
+        if len(pk_names) != len(pk_values):
+            raise NotFoundError(
+                "Need {} primary key value{}".format(
+                    len(pk_names), "" if len(pk_names) == 1 else "s"
+                )
+            )
+
         wheres = ["[{}] = ?".format(pk_name) for pk_name in pk_names]
         rows = self.rows_where(" and ".join(wheres), pk_values)
         try:
diff --git a/tests/test_get.py b/tests/test_get.py
index bd79490..ae5ffdf 100644
--- a/tests/test_get.py
+++ b/tests/test_get.py
@@ -1,4 +1,5 @@
 import pytest
+from sqlite_utils.db import NotFoundError
 
 
 def test_get_rowid(fresh_db):
@@ -11,10 +12,25 @@ def test_get_rowid(fresh_db):
 def test_get_primary_key(fresh_db):
     dogs = fresh_db["dogs"]
     cleo = {"name": "Cleo", "age": 4, "id": 5}
-    row_id = dogs.insert(cleo, pk="id").last_pk
+    last_pk = dogs.insert(cleo, pk="id").last_pk
+    assert 5 == last_pk
     assert cleo == dogs.get(5)
 
 
+@pytest.mark.parametrize(
+    "argument,expected_msg",
+    [(100, None), (None, None), ((1, 2), "Need 1 primary key value"), ("2", None)],
+)
+def test_get_not_found(argument, expected_msg, fresh_db):
+    fresh_db["dogs"].insert(
+        {"id": 1, "name": "Cleo", "age": 4, "is_good": True}, pk="id"
+    )
+    with pytest.raises(NotFoundError) as excinfo:
+        fresh_db["dogs"].get(argument)
+    if expected_msg is not None:
+        assert expected_msg == excinfo.value.args[0]
+
+
 @pytest.mark.parametrize(
     "where,where_args,expected_ids",
     [