This observational study described the prevalence and associated factors of substance use (SU) among adolescent gamblers, comparing data from pre and post pandemic surveys among 7,960 adolescents between 14 and 18 years old from a Nationwide Population-Based Study (ESTUDES) conducted in Spain. The independent effect of socio-demographic characteristics, video game and internet-related variables, perceived health risks from consumption, and the perceived availability of substances on SU in adolescent gamblers were estimated. Alcohol and marijuana were the most commonly reported substances, and they were the only ones that presented a significant reduction in prevalence in 2021. Adolescent gamblers who reported having easy access to substances were more likely to consume alcohol (OR:2.92, 95%CI:1.95-4.37), marijuana (OR:5.98, 95%CI:4.72-7.57), TSSp (OR:2.12, 95%CI:1.70-2.65), cocaine (OR:5.15, 95%CI:3.81-6.98) and new substances (OR:2.25, 95%CI:1. 80-2.82). Likewise, adolescents who gambled and did not perceive health-related risk for using were more likely to consume alcohol (OR:1.52, 95%CI:1.21-1.90), marijuana (OR:3.16, 95%CI:2.64-3.77), TSSp (OR:1.84, 95%CI:1.41-2.40), cocaine (OR:5.44, 95%CI:3.57-8.28) and other substances (OR:3.20, 95%CI:2.09-4.90). Among the implications are the development of programs aimed at higher-risk consumption, the continuation and strengthening of programs to raise awareness of the risk of drug consumption, and the re-evaluation of current measures to control access to legal and illegal substances by adolescents.