Word-of-Mouth (WOM) is an effective promotional strategy for appealing consumers of fast food restaurants. A lot of consumers choose to receive information through WOM when planning to visit a certain fast food restaurant. Fast food industry is on growing day by day in Pakistan. There are numerous national and international fast food restaurant brands and a rigid competition among them in the country. Purpose of the study is to measure the impact of positive and negative WOM on purchase intention among consumers of fast food restaurants in Pakistan. Also, mediating roles of loyalty and attitude between WOM (i.e. positive and negative Word-of-Mouth) and purchase intention are measured. Convenience sampling technique with a sample size of 254 consumers is applied. A personally administered questionnaire with five point likert scale is used to collect data from consumers. Collected data is then analyzed by using multiple regression analysis via Statistical Package for Social Sciences (SPSS) version 23. Whereas, mediation effects are measured by Preacher and Hayes method. Results revealed that positive Word-of-Mouth (PWOM) has positive and significant impact on purchase intention (PI), loyalty, and attitude whether negative Word-of-Mouth (NWOM) has negative and significant impact on purchase intention, loyalty, and attitude. Other findings showed that loyalty and attitude have positive and significant impact on purchase intention towards a certain fast food restaurant. Study also exhibits partial mediation effect. Academic, managerial, and future implications are also discussed.