Concern about the development of behavioral addictions in adolescence, including gambling, has increased in recent years. Evidence shows that problem gambling can lead to personal, social, or health problems. However, even though gambling is an illegal activity, studies on this problem are quite limited in Spain. The main objective of this study was to analyze the prevalence of gambling in adolescents in Spain. Moreover, gambling behaviors were examined according to gender and age, and their possible relationship with several mental health indicators was analyzed. The results showed that 20.6% of the adolescents who participated in the study had gambled money in the past year. The highest gambling prevalence was found in boys and in adolescents from the age of 16 years old. Moreover, the results showed that gambling behavior was related to different mental health indicators.