Wildlife rescue, rehabilitation, and release is a global practice with a broad body of scientific literature; nonetheless, no studies have assessed and quantified the methodological rigour and reporting quality of this literature. In this PRISMA systematic review, we assessed and quantified the reporting of controls, randomisation, blinding, experimental animal data, and housing and husbandry data in 152 primary studies on wildlife rescue, rehabilitation, and release published between 1980 and 2021. We then tested for associations between reporting and study characteristics. Of the 152 reviewed studies, one study reported a control, randomisation, and blinding; 17 studies reported species, age, sex, weight, and body condition; and 14 studies reported housing size, housing location, type of food, provision of water, and provision of enrichment. No study reported all 13 of these elements. Studies published in veterinary-focused journals reported lower methodological rigour and had lower reporting quality than studies published in other types of journals. Studies on mammals had higher reporting quality than studies on birds and on reptiles, and studies that included the word "welfare" had higher reporting quality than studies that did not. The overall low methodological rigour and reporting quality of the literature limits study replicability and applicability and impedes meta-analyses.