Bullying research among preschoolers and the early grades of primary school is still scarce. With the aid of a set of cartoons representing prototypical bullying scenes, we interview 120 schoolchildren (50% girls) from kindergarten to third grade (age range: 5.44–9.58) from three mainstream public schools located in the eastern Community of Madrid, in order to analyse their perceptions regarding this phenomenon. Results show that 94.2% (n = 113) of schoolchildren are able to recognize when a partner is victimized. Nevertheless, significant differences were found by grade (p = 0.017), with kindergarteners giving more responses classified as one-off aggressions. Most students (n = 102) empathize with the victims´ emotions and condemn the bullies’ behavior, regardless of their gender (p = 0.637) or grade (p = 0.578). A total of 53.9% (n = 64) of students think these bullying situations are partly caused by previous conflicts; girls are inclined to think this more often than boys (p = 0.003). Furthermore, 53.8% (n = 64) of the students would request help from their schoolteachers if they were bullied, with no statistically significant differences by gender (p = 0.254) or by grade (p = 0.133). These results serve as a rationale to develop bullying prevention programs from a very early school age to provide information regarding its causation and coping strategies, among others.