European countries are characterised by their ethnic and migratory diversity. However, migrant and ethnic minority populations continue to exhibit higher rates of mental health disorders, such as depression. How can these differences be explained? Beyond socioeconomic factors influencinf mental health status and acces to mental health services, research has shown that healthcare providers, such as General Practitioners (GPs), may have ethnic biases that contribute to ethnic inequalities. The aim of this thesis is to describe the extent to which biases among GPs are present and how they influence their medical decisions toward migrant patients with depression. The results highlight the importance of GPs to be aware of and address their implicit and explicit biases toward migrant and ethnic minority populations to mitigate unintentional discrimination.