Discriminatory bullying based on differences in special educational needs or disability threatens the healthy development of adolescents. The study aims to find out whether self-esteem, empathy, and social skills are predictors of this discriminatory bullying (aggression and victimization). A sample of 1,640 adolescents aged 11 to 20, of which half are from Spain (48.8% male and 51.2% female) and half from Ecuador (49.3% men and 50.7% women), participated in the study by completing a battery of self-report questionnaires. The results of the structural equation models show that in both countries victimization and aggression are predicted negatively by self-confidence and positively by self-deprecation; assertiveness is a positive predictor of aggression and a negative predictor of victimization. Differences are observed between the two countries in the role of social skills (communication and conflict resolution) and empathy. These results are discussed in relation to the nature of this discriminatory bullying and preventive educational programs.