In the early 1990s, a series of seminal research studies were published on substance use disorders among Latino adolescents in Miami-Dade County, Florida. Expanding upon these studies, the aims of the present dissertation project were to (1) Determine whether the following adolescents' and parents' characteristics/cultural values are associated with current (past 30 days) or lifetime (ever) alcohol or marijuana use among Latino adolescents: sex, age, country of birth, GPA, family's socioeconomic status, living with both parents, mother's highest level of education, father's highest level of education, Familism Support, Familism Obligations, Familism Referents, Respect, Religion, Traditional Gender Roles, Independence and Self-Reliance; (2) Assess if recreational activities (sports participation, after-school activities and volunteering) moderate the association between Latino adolescents' friends' age, sex, and ethnicity and Latino adolescents' current alcohol or marijuana use and; (3) Assess if recreational activities moderate the association between Latino adolescents' perceptions of friends' alcohol or marijuana use and Latino adolescents' current alcohol or marijuana use. vi This cross-sectional dissertation study used survey data from 193 Latino adolescent males and females (15.7 ± 1.6 years old; 55.4% females, 44.6% males) in Miami-Dade County collected in 2016-2017. Analyses included t-tests, chi-square tests and logistic regressions. Being born in the U.S. increased the risk of current alcohol use. Identifying more strongly with the cultural value Religion decreased the risk of current alcohol use and current marijuana use. Participants who reported having no close friends who use alcohol were less likely to currently (within past 30 days) use alcohol themselves when compared to participants who reported having at least one close friend who uses alcohol. The interaction between participation in sports activities and reporting having friends who use alcohol on outcome currently using alcohol was significant. Participants who reported having no close friends who use marijuana were less likely to currently use marijuana themselves. Findings from this study suggest that factors contributing to substance use among Latino adolescents throughout the United States may be different than those which play a role among the unique Latino adolescent population in Miami-Dade County. This study further validated what has been shown in the general U.S. population: adolescents who perceive their friends to be using alcohol or marijuana are more likely to use alcohol or marijuana, respectively, themselves. Further research is suggested to determine the role of recreational activities in alcohol and marijuana use among Latino adolescents. vii