The Honda Civic Si is a sport compact trim of Honda's Civic. The Si trim was introduced for the third generation of Honda Civics in both Japan and North America. In Canada and elsewhere, the trim became known as the SiR for the sixth and seventh generations as the "Si" badge was used for the equivalent to the USDM Civic EX model.

Sport compact is a United States marketing classification for a high-performance version of a compact or a subcompact car. There is no precise definition, and the description is applied to various models for promotional purposes.