Abstract : The objective of the work at hand is to give an overview of the work done so far regarding legible robot behavior. Legibility roughly means that a person intuitively understands the intentions of a robot. To this end, we systematically reviewed 32 articles published in the primary HRI publication venues. The purpose of the following review is to answer the questions: How do other researchers define legibility?, How can legibility be measured? How can one implement legible robot behavior?, and Which factors are correlated with legibility?