Research on cyberbullying started at the beginning of the 21st century and the number of studies on the topic is increasing very rapidly. Nevertheless, the criteria used to define the phenomenon and evaluation strategies are still under debate. Therefore, it is still difficult to compare the findings among the studies or to describe their prevalence in different geographic areas or time points. Thus, the current systematic review has been conducted with the objective of describing the studies on the phenomenon in Spain taking into account its different definitions and evaluation strategies in relation to its prevalence. After conducting systematic searches and applying the inclusion criteria, 29 articles reporting the results of 21 different studies were included. It was found that the number of studies on the topic in Spain is growing and that most of the definitions include the criteria of repetition, intention, and power imbalance. It was also found that timeframes and cut-off points varied greatly among the studies. All the studies used self-reports with one-item or multi-item instruments. The prevalence also varied depending on the evaluation strategies and when assessed with multi-item instruments it was about twice as high as when assessed with one-item instruments. It is suggested that specific instruments should be chosen depending on the research questions posed in each investigation and that it could be useful to unify the criteria for further advancement of the field.