Art Deco buildings are brick or stone and are characterized by geometric decoration. Zig-zag patterns and stylized natural forms are common. The most familiar type of the style in Cincinnati is the box-like, two-story, flat-roofed, brick apartment building. Windows are sash or casement. Glass block windows are common. Other features include decorative brickwork in contrasting colors and stepped parapets (walls rising above the roof). Art Deco apartment buildings are found in many areas of Cincinnati including Westwood, Roselawn, and Oakley.

The Art Deco style developed after the Paris Exposition Internationale des Arts Decoratifs et Industrieles Modernes in 1925. Beginning as a style of ornamentation, Art Deco was exemplified in trains, radios, jewelry, furniture, and countless other items. It also evolved into a style of architecture. Office buildings, post offices, movie theaters and apartment buildings were built in the Art Deco style. Single-family houses of the style are rare.

Moderne, a style that followed Art Deco, is closely related but lacks the intricate geometric Art Deco ornamentation. It is also known as streamlined architecture: banded windows, smooth stone surfaces, and stainless steel trim and railings are characteristic of this style. Union Terminal is the best example of Moderne in Cincinnati. There are few houses of this style.