diff --git a/amanuensis/backend/lexicon.py b/amanuensis/backend/lexicon.py
new file mode 100644
index 0000000..089b8e3
--- /dev/null
+++ b/amanuensis/backend/lexicon.py
@@ -0,0 +1,51 @@
+"""
+Lexicon query interface
+"""
+
+import re
+
+from sqlalchemy import select, func
+
+from amanuensis.db import DbContext, Lexicon
+from amanuensis.errors import ArgumentError
+
+
+RE_ALPHANUM_DASH_UNDER = re.compile(r'^[A-Za-z0-9-_]*$')
+
+
+def create_lexicon(
+    db: DbContext,
+    name: str,
+    title: str,
+    prompt: str) -> Lexicon:
+    """
+    Create a new lexicon.
+    """
+    # Verify name
+    if not isinstance(name, str):
+        raise ArgumentError('Lexicon name must be a string')
+    if not name.strip():
+        raise ArgumentError('Lexicon name must not be blank')
+    if not RE_ALPHANUM_DASH_UNDER.match(name):
+        raise ArgumentError('Lexicon name may only contain alphanumerics, dash, and underscore')
+
+    # Verify title
+    if title is not None and not isinstance(name, str):
+        raise ArgumentError('Lexicon name must be a string')
+
+    # Verify prompt
+    if not isinstance(prompt, str):
+        raise ArgumentError('Lexicon prompt must be a string')
+
+    # Query the db to make sure the lexicon name isn't taken
+    if db.session.query(func.count(Lexicon.id)).filter(Lexicon.name == name).scalar() > 0:
+        raise ArgumentError('Lexicon name is already taken')
+
+    new_lexicon = Lexicon(
+        name=name,
+        title=title,
+        prompt=prompt,
+    )
+    db.session.add(new_lexicon)
+    db.session.commit()
+    return new_lexicon
diff --git a/tests/test_db.py b/tests/test_db.py
index 866e408..68ae2c1 100644
--- a/tests/test_db.py
+++ b/tests/test_db.py
@@ -1,7 +1,10 @@
+import datetime
+
 import pytest
 from sqlalchemy import func
 
 from amanuensis.db import *
+import amanuensis.backend.lexicon as lexiq
 import amanuensis.backend.user as userq
 from amanuensis.errors import ArgumentError
 
@@ -62,3 +65,39 @@ def test_create_user(db):
     user2_kw = {**kwargs, 'username': 'user2', 'display_name': None}
     user2 = userq.create_user(db, **user2_kw)
     assert user2.display_name is not None
+
+
+def test_create_lexicon(db):
+    """Test new game creation."""
+    kwargs = {
+        'name': 'Test',
+        'title': None,
+        'prompt': 'A test Lexicon game'
+    }
+    # Test name constraints
+    with pytest.raises(ArgumentError):
+        lexiq.create_lexicon(db, **{**kwargs, 'name': None})
+    with pytest.raises(ArgumentError):
+        lexiq.create_lexicon(db, **{**kwargs, 'name': ''})
+    with pytest.raises(ArgumentError):
+        lexiq.create_lexicon(db, **{**kwargs, 'name': ' '})
+    with pytest.raises(ArgumentError):
+        lexiq.create_lexicon(db, **{**kwargs, 'name': '..'})
+    with pytest.raises(ArgumentError):
+        lexiq.create_lexicon(db, **{**kwargs, 'name': '\x00'})
+    with pytest.raises(ArgumentError):
+        lexiq.create_lexicon(db, **{**kwargs, 'name': 'space in name'})
+
+    # Validate that creation populates fields, including timestamps
+    before = datetime.datetime.utcnow() - datetime.timedelta(seconds=1)
+    new_lexicon = lexiq.create_lexicon(db, **kwargs)
+    after = datetime.datetime.utcnow() + datetime.timedelta(seconds=1)
+    assert new_lexicon
+    assert new_lexicon.id is not None
+    assert new_lexicon.created is not None
+    assert before < new_lexicon.created
+    assert new_lexicon.created < after
+
+    # No duplicate lexicon names
+    with pytest.raises(ArgumentError):
+        duplicate = lexiq.create_lexicon(db, **kwargs)