Electronic word of mouth (eWOM) significantly affects the consumer decision-making process. A number of studies investigated why consumers provide eWOM communications. Existing literature has contradicting factors regarding factors affect eWOM providing behaviour. This study aims to evaluate factors affecting eWOM providing behaviour by performing a systematic review and weight analysis of existing research outputs. Based on the result of weight analysis it was found that the best predictors of eWOM providing behaviour are involvement, self-enhancement, and trust in web eWOM services. Scholars can use the results of this study when making decisions regarding the inclusion of factors in their research. Practitioners can pay more attention to the best predictors.