Words matter when describing people involved in the criminal justice system because language can have a significant impact upon health, wellbeing, and access to health information and services. However, terminology used in policies, programs, and research publications is often derogatory, stigmatizing, and dehumanizing. In response, health experts from Europe, the United States, and Australia recommend that healthcare professionals, researchers, and policy makers working with people in detention follow key principles that foster constructive and humanizing language. These principles include: engage people and respect their preferences; use stigma-free and accurate language; prioritize individuals over their characteristics; and cultivate self-awareness. The article offers examples of problematic terms to be avoided because they do not convey respect for incarcerated people and propose preferred wording which requires contextualization to local language, culture, and environment. The use of respectful and appropriate language is a cornerstone of reducing harm and suffering when working with people involved in the criminal justice system; the use of stigmatizing and dehumanizing language must therefore come to an end.