In scientific and popular psychological literature, self-esteem is often mentioned as an indicator of mental health, mature personality and adaptation of an individual. However, recently there has been a growing number of contradictory findings on self-esteem, the reason for which can be found in an old-fashioned approach to investigating self-esteem, i.e. neglecting various aspects of self-esteem, as well as different measures for self-esteem. The aim of this article is to familiarize researchers with new insights in self-esteem research, point out the complexity of the construct and give guidelines for future research. The article explains why the use of different self-esteem measures often results in contradictory findings concerning self-esteem level. We also introduce the construct of self-esteem security that can shed light on the abovementioned contradictory findings. Furthermore, the definition of self-esteem security as well as various operationalisations of this construct are given, and commonalities and differences with related constructs explained. Finally, the article presents results of recent self-esteem research and new findings in this area.