This is a list of notable roller derby leagues, and may include those that are no longer in existence. Existence dates, where known, are included to provide a timeline charting the sport's growth cycles. The list may currently make distinctions according to each organization's professional/amateur business structure and active/defunct status, and is subdivided by gender (female or male-only, or co-ed) and age (adult versus junior). Within each subcategory, leagues are then listed according to region, by country and city. Countries with larger numbers of leagues, such as the United States and Canada, are further subdivided by state and province.