The use of person-centred language is well accepted regarding substance use and infectious disease healthcare and research, and appropriate acronyms have become commonplace, e.g., "people who inject drugs (PWID)" has mostly replaced phrases like "injecting drugs users". However, the use of the term's 'prisoner' or 'prisoners' remains common. Although less common, terms such as 'offenders' and 'inmates' are also still used on occasion. This persists despite calls from people with lived experience of incarceration, and fellow academics, to stop using these terms. Given the considerable overlap between substance use, infectious diseases, and incarceration, in this commentary we discuss how they interact, including the stigma that is common to each. We propose that using person-centred language (i.e., people in prison or people formerly in prison) needs to become the default language used when presenting research related to people in prison or people formerly in prison. This is a much-needed step in efforts to overcome the continued stigma that people in prison face while incarcerated from prison officers and other employees, including healthcare providers. Likewise, overcoming stigma, including legalised discrimination, that follows people who were formerly in prison upon gaining their freedom is critical, as this impacts their health and related social determinants, including employment and housing.