This report is an extension of the 2018 report, "Teen Sport in America: Why Participation Matters Report" which set out to identify the health, academic, and psychological benefits that teen girls obtain on a sport-by-sport basis. The original 2018 Teen Sport report provided evidence of the important role that sports can play in promoting positive development among a large national sample of teens in high school. However, the report did not take into consideration how girls fare from their sport participation specifically. This current report sets out to examine the ways in which sports participation is related to positive teen girls' well-being. It looks at across a number of positive outcomes of well-being to get a more informed profile of the influence of sports participation on teen girls' health, academic achievement, and psychological well-being. The authors also considered differences by (1) the number of sports in which girls participated; and (2) by type of sport. This involved a close examination of the strengths and challenges of each of the 20 most popular teen sports in the United States for promoting teen girls' well-being across a wide range of important behaviors and outcomes within health, academic achievement, and psychological well-being. [For the 2018 report, see ED588346.]