Chihuahua, Chihuahua, Mexico cholo society's “rules” for the participation of males and females in street-fighting are examined as reported in interview contexts with youth of both sexes. Interview accounts are then compared to an observed instance of use of physical force by females against males in that city. Barrio peer group dynamics are explored and contrasted with the dynamics of similar groups in the northern Mexican cities of Nogales, Sonora, and Tijuana, Baja California, that do not share Chihuahua's unique characteristics.