Dennis Cliff Smith Jr. (born November 25, 1997) is an American professional basketball player for the Brooklyn Nets of the National Basketball Association (NBA). He attended North Carolina State University for one season of college basketball and earned second-team all-conference honors in the Atlantic Coast Conference (ACC) as a freshman as well as ACC Freshman of the Year.

Smith was selected ninth overall in the 2017 NBA draft by the Dallas Mavericks. Smith spent two seasons in Dallas before being traded to the New York Knicks in January 2019. He was traded to the Detroit Pistons in February 2021 and later joined the Portland Trail Blazers as a free agent in September of the same year. He was waived by the Blazers in February 2022 after suffering a right elbow injury and signed with the Charlotte Hornets in the 2022 off-season.