In the past 20 years, Political Science research has increasingly focused on urban and local politics. We systematically review this literature and find that smaller cities are disproportionally underrepresented, particularly outside the United States. Smaller cities exhibit economic, social, and political patterns that differ from those in large metropolitan areas. Using administrative data and existing research, we show how cities of different sizes vary in their demographic characteristics; citizens’ preferences; resources and capacity; intergovernmental relationships; and electoral politics. These patterns indicate the potential to update existing theories in Political Science, including those about gender and political participation, second-order elections, and intergovernmental relationships. We suggest that scholars consider how smaller cities might differ from larger cities and include smaller municipalities in their case study research. We also highlight political issues unique to small cities as new areas of inquiry.