Several studies in the literature indicate the link between socio-psychological factors at work with the degree of satisfaction or perceived happiness. However, there are still few analyzes that expressly address this relationship in the public sector workers, compared to those in the private sector. This paper aims to find out if the public sector employees are happier than the private sector, by associating happiness to some of these factors in Spain. Results show that employees in the public sector are indeed happier than those in private one. In terms of pay, safety and perceived stress levels, there are association relationships to employee happiness. This research provides very useful information for those firm managers who are responsible for human resources policies related to these factors: salary, security and stress.