Abstract Background Harm reduction services that employ or are operated by people who use drugs are an effective means of mitigating overdose risks and other drug-related harms. However, stereotypes portraying people who use criminalized drugs as incapable caregivers persist. This is especially true for women who use drugs, and to a greater extent racialized women, who are characterized as having diverged from traditional ideals of womanhood as a result of drug-user stigma and the intersections of gender- and class-based and racist stereotypes. In an effort to identify and understand how women who use drugs practise care through harm reduction, we explored the experiences of women accessing a low-threshold supervised consumption site exclusively for women (transgender and non-binary inclusive) in Vancouver, Canada. Methods Data were drawn from research conducted from May 2017 to June 2018 exploring women’s experiences accessing the supervised consumption site during an overdose crisis. Data included forty-five semistructured interviews with women recruited from the site, analysed thematically to explore practices of care through harm reduction. Findings Participants reported engaging in both formal and informal care. Acts of care included interventions that both aligned with and deviated from conventional understandings of care practices, including overdose reversal and education, overdose supervision/care, and assisted injection. Conclusion The boundary between formal and informal harm reduction care is fluid. Women who use drugs engage in harm reduction across these borders with acts of care that align with or fill the gaps in current harm reduction services in order to meet the needs of drug-using communities, challenging negative stereotypes of women who use drugs. However, these caregiving practices can increase risks to care providers’ physical, mental, and emotional health and wellness. Increased financial, social, and institutional supports, including safer supply, assisted injection, and community resources, are needed to better support women as they continue to engage in harm reduction care.