Sports are commonly defined as games that require physical activity and competition under an explicit set of rules. While some people believe that spectators are an essential part of sports, others maintain that sports include any physical activity carried out for enjoyment. To many, sports suggest high-stakes, competitive games with participants who are highly skilled, but a larger number of people recognize sports as fun and playful activities for participants with a wide range of abilities. This entry uses the latter sense to describe sports as a challenging, enjoyable, and healthy activity for individuals with intellectual and developmental disabilities. Specific attention is paid to how sports can be modified to accommodate all players, including those with developmental and intellectual disorders.