Accessory commercial units (ACUs) are additional units on or within a residential property that are designed for commercial use. These units can be standalone structures or attached to homes, such as converted garage space. ACUs are the commercial equivalent of residential accessory dwelling units (ADUs), which are additional housing units on the property of a single-family home. While ADUs are more prevalent, entrepreneurs and city planners have become more interested in ACUs in the wake of the COVID-19 pandemic, which increased the demand for in-home and affordable workspaces. However, in most municipalities, zoning laws do not allow ACUs.

Some states and municipalities are taking steps to change this. Pomona, Califonia, and Raleigh, North Carolina, have legalized some types of ACUs. Other cities, including Portland, New Orleans, and Minneapolis, have legalized in-home limited commercial activity. In 2025, the Connecticut House of Representatives considered a bill to allow ACUs statewide, but the bill did not progress.