Background: Drug use disorder (DUD) is a serious health condition that imposes a heavy burden on the persons who have a drug addiction experience and their families, especially in countries, such as Myanmar, where few formal support mechanisms are in place and repressive drug laws exacerbate the situation. Yet, in Myanmar, little is known about how informal caregivers are affected. Objectives: This qualitative study aims at exploring the socioeconomic and psychological burden that informal caregivers in Myanmar encounter, coping strategies they employ, as well as barriers to coping they face. Methods: Thirty primary informal caregivers were chosen purposively from a mental health hospital in Yangon for in-depth interviews. The recorded interviews were transcribed and the data were analysed using framework analysis. Findings: The results revealed that financial constraint, income loss, social limitation and negative impact on family cohesion are important dimensions of socioeconomic burden, whereas sadness, anger, helplessness, worry, fear and guilt are the main psychological distress factors encountered by caregivers of persons with DUD. Key coping strategies employed by caregivers include religious coping, financial coping, acceptance and planning. Moreover, perceived stigma towards persons with DUD and their caregivers was very high and caregivers received hardly any social support, inter alia because of the country's drug law which reinforces stigma and discrimination. Neither the government nor any other organization in Myanmar provided financial support to the caregivers. Conclusions: The results of this study showed that caring for persons with DUD has devastating effects on caregivers and their families. While the 2018 National Drug Control Policy can potentially help alleviate the burden on substance users and their families, further amendments of the existing drug law are urgently needed. Moreover, strengthening prevention and harm reduction approaches, improving treatment and rehabilitation services, as well as stigma-reducing educational campaigns should be considered a priority.