Diagrammatic depictions of evolutionary relationships play an increasingly important role in scientific and educational literature. Reading evolutionary trees is seen as a major challenge for biologists in learning about evolution and its applications in research. The skills needed to read, interpret, and construct evolutionary trees are subsumed under the term "tree-thinking, " which can be divided into "tree-reading" and "tree-building. " The purpose of this paper is two-fold. First, we review relevant literature on tree-reading skills to examine regularly reported skills for an up-todate overview of the topic and to determine where further investigation might be needed. Second, we compare and contrast published skills and skill systems to highlight commonalities and differences using a published hierarchical system as a framework and integrating the skills identified by other authors by arranging them with their corresponding skills within the framework. The resulting insights suggest a possible synthetic tree-reading model. By bringing together the relevant literature about tree-reading skills, we show that research on tree-thinking skills has until now been conducted mainly following theoretical or observational approaches, often lacking cross-references linking different works; this has resulted in multiple approaches. Furthermore, as most published systems have not been empirically tested, it seems useful to collect existing findings for empirical testing to create a synthetic tree-reading skill model that can be used by educators to structure and organize their learning environments. Teaching the subdomains of tree-reading in order of difficulty can facilitate the entire learning process. Furthermore, the skill model can be used to design testing instruments for education and research that incorporate the full range of tree-reading subdomains and thus, may be better suited to distinguish more advanced learners from less advanced ones.