In this study we explored the relationship between subjective and objective measures of motor impulsivity in Spanish adolescents (N= 78). We used an emotional Go/No-Go task to investigate the potential modulation of behavioral inhibition by the affective valence of the stimuli, and whether such modulation was influenced by the adolescent’s level of impulsivity. Variables related to level of impulsivity, such as self-control and sincerity were also assessed. Our results reveal a significant relationship between subjective and behavioral measures of impulsivity, and suggest adolescents were capable of evaluating themselves on this variable. Additionally, we obtained a positive correlation between impulsivity and sincerity, as well as an inverse relationship between impulsivity and self-control. We also observed a significant emotional modulation in terms of both accuracy (i.e., rates of hits and false alarms) and speed of processing (i.e., reaction times) of the affective images. Emotional modulation, however, was not altered by the adolescents’ level of impulsivity, possibly due to the developmental stage of the sample and the relationship between impulsivity and executive function at that stage.