This study presents the first evaluation of Dat-e Adolescence, a dating violence prevention program aimed at adolescents in Spain. A cluster randomized control trial was used involving two groups (a control group and experimental group) and two waves (pre-test and post-test six months apart). 1,764 students from across seven state high schools in Andalucía (southern Spain) participated in the study (856 in the control group and 908 in the experimental group); 52.3% were boys (n = 918), with ages ranging from 11 to 19 years (average age = 14.73; SD = 1.34). Efficacy evaluation was analyzed using Latent Change Score Models and showed that the program did not impact on physical, psychological or online aggression and victimization, nor did it modify couple quality. It was, however, effective at modifying myths about romantic love, improving self-esteem, and improving anger regulation, as a trend. These initial results are promising and represent one of the first prevention programs evaluated in this country. Future follow-up will allow us to verify whether these results remain stable in the medium term.