Anthropogenic environmental changes are causing severe damage to the natural and social systems on which human health depends. The environmental impacts of the manufacture, use, and disposal of antimicrobials cannot be underestimated. This article explores the meaning of environmental sustainability and four sustainability principles (prevention, patient engagement, lean service delivery, and low carbon alternatives) that infection specialists can apply to support environmental sustainability in health systems. To prevent inappropriate use of antimicrobials and consequent antimicrobial resistance (AMR) requires international, national, and local surveillance plans and action supporting antimicrobial stewardship (AMS). Engaging patients in addressing environmental sustainability, for example through public awareness campaigns about the appropriate disposal of unused and expired antimicrobials, could drive environmentally sustainable changes. Streamlining service delivery may include using innovative methods such as C-reactive protein (CRP), procalcitonin (PCT), or genotype-guided point of care testing (POCT) to reduce unnecessary antimicrobial prescribing and risk of adverse effects. Infection specialists can assess and advise on lower carbon alternatives such as choosing oral (PO) over intravenous (IV) antimicrobials where clinically appropriate. By applying sustainability principles, infection specialists can promote the effective use of healthcare resources, improve care quality, protect the environment, and prevent harm to current and future generations.