The amount of online reviews is growing significantly. Between 2014 and 2017, the number of reviews for TripAdvisor grew by 300% and for Yelp by 208%. However, not all online reviews are equally valuable. Some reviews are perceived to be more helpful or trustworthy then others. Hence, plethora of scholars have investigated the role of online reviews and researched factors and characteristics determining its helpfulness. Nevertheless, mixed findings were found. Consequently, the purpose of our paper is to present a holistic and representative analysis of the literature on factors indicating the helpfulness of online reviews. In total, we analyzed 81 journal articles and inductively created a framework resulting in four dimensions: review-related factors, reviewer-related factors, reader related factors and environment-related factors. The results reveled that researchers mainly focused on factors of the first two dimensions and that the findings are inconsistent and need to be further researched in the future.