Background: Rates of death from opioid overdose continue to rise in the United States. One harm reduction strategy designed to reduce fatal overdose risk among people who inject drugs (PWID) is an advisory to not use drugs alone. However, the feasibility and acceptability of this message have not been evaluated. Objectives: This paper explores the drug use practices of young PWID related to injecting alone and reasons for doing so. Methods: From 2015 to 2016, 23 in-depth interviews were completed in Baltimore, Maryland with young PWID. Participants were recruited through street/venue-based outreach and word of mouth. Inclusion criteria were 1) age 18-30 and 2) self-report injection drug use in past 6 months. Participants were asked about drug use history, overdose knowledge/experiences, and injection-related practices including when, where, and with whom drugs were injected. Results: Injecting drugs alone was common among members of this sample. Reasons for injecting alone included 1) the desire to alleviate withdrawal symptoms, 2) feelings of shame regarding one’s drug use, 3) lack of knowledge about Good Samaritan Laws, 4) financial circumstances, and 5) a lack of trusted peers with whom to inject, often due to disrupted social networks. Conclusions: Young PWID inject alone for a variety of reasons, putting them at increased risk of fatal overdose. These findings demonstrate that “don’t use alone” messages may not be sufficient given the complex realities of PWID’s injection practices. Harm reduction programs employing such messaging should also offer alternative options for overdose prevention/risk reduction for those who do inject alone.