The consumption of cannabis and alcohol results in a variety of effects on the psychic functions of young users. Notwithstanding their widespread and prevalent use, the impact of these drugs on sexual health remains unknown. Thus, the aim of this study is to analyse the influence of alcohol and cannabis consumption on sexual function in young people. An observational study was conducted in 274 participants aged 18–30 years. The following selection tools were used: Alcohol Use Disorders Identification Test, Cannabis Abuse Screening Test (CAST), and Changes in Sexual Functioning Questionnaire Short-Form. Participants who were at high risk of having cannabis-related problems performed better on the CAST concerning sexual function, arousal, and orgasm. Participants at high risk had higher arousal and orgasm scores than those who were not at risk for cannabis problems. Improvements in sexual function were found between people who were at high risk of having alcohol problems and those who were not at risk. Sexual function in young people who use cannabis and alcohol more frequently was shown to be better than in those who do not use either, highlighting the need for more information aimed at the young population.