BACKGROUND:Mental health problems are the main cause of sick leave in today’s working age population. Employers are responsible for their employees’ work environment and preventing work-related illnesses, but their knowledge regarding mental health problems is lacking. Employer beliefs and support strategies need further exploration. OBJECTIVE:To explore employers’ beliefs, knowledge and strategies use in providing support to employees with mental health problems. METHODS:This grounded theory study comprised 24 interviews with employers in a variety of workplaces, and included women and men in large and small organizations in a Swedish context. RESULTS:Two categories related to the aims emerged: comprehending mental health problems is complex, and lacking established conditions to support work. The results show that employers seek to support employees with mental health problems but have low expectations and lack knowledge and strategies. Employers acknowledged experiences of inadequate support and collaboration from other actors in the return-to-work (RTW) process. CONCLUSIONS:To close the service gap and improve the RTW process, employers need to increase their mental health literacy. Other actors need to improve their understanding of employer situations and provide them with necessary support.