Gamification is an emerging technique which utilises the “fun theory” mainly to motivate people to change their perception and attitude towards certain subjects. Within enterprises, gamification is used to motivate employees to do their tasks more efficiently and perhaps more enjoyably and sometimes to increase their feeling of being members of the enterprise as a community. While the literature has often emphasised the positive side of gamification, mainly from economic and business perspectives, little emphasis has been paid to the ethical use of gamification within enterprises. In this paper we report an empirical research to explore the ethical aspects of using gamification. We follow a mixed methods approach involving participants who are gamification experts, employees and managers. Our findings show that, for gamification, there is a fine line between being a positive tool to motivate employees and being a source of tension and pressure which could then affect the social and mental well-being within the workplace. This paper will evaluate that dual effect and clarify that fine line.