By introducing psychological theories into entrepreneurship research field, this thesis aims to investigate the relationship between self-employment and workplace wellbeing. The thesis consists of three empirical studies, which set out to answer the following questions: 1) What are the differences of workplace wellbeing between the self-employed and employees? 2) What factors contribute to workplace wellbeing in both direct and indirect ways? 3) What is the relationship between negative workplace wellbeing and positive wellbeing, 4) How does coping mechanism reduce negative workplace wellbeing and enhance positive wellbeing? Moreover, this thesis also examines the specific issues of self-employment, such as workplace wellbeing of the self-employed under the poverty line and the differences between the self-employed with hiring employees and the self-employed without hiring any employee. This quantitative and comparative thesis has employed the matching approach to overcome selection bias and combined with other statistical methods such as CFA, SEM and moderating hierarchy regression to test the conceptual models empirically. The data used for this research is sourced from the Understanding Society, the largest household panel data in the UK. This thesis found that the self-employed experience higher positive workplace wellbeing than employees. The self-employed with hiring employees experience a significantly higher level of negative workplace wellbeing than employees. However, the self-employed without hiring any employee experience significant lower negative workplace wellbeing. Moreover, this thesis found that job demand and job control contribute to negative workplace wellbeing directly, and the relationship can be partly moderated by social support. In addition, the thesis has tested the relationship between the positive workplace wellbeing and negative workplace wellbeing, which has been verified as negative correlations. Lastly, the results showed self-efficacy is an effective coping factor to reduce negative wellbeing and enhance positive wellbeing.