<p>Citric acid (CA), a naturally occurring organic acid found in citrus fruits, has emerged as an effective catalyst in various synthetic routes. Citric acid is a great option for catalyzing reactions for sustainable chemistry. Its potential as a green catalyst is due to its environmentally friendly nature and ability to catalyze reactions well under moderate conditions. Its application as a photo-catalyst further demonstrates its adaptability in promoting reactions, broadening its applications in green chemistry. This article summarizes its wide range of uses as a catalyst, highlighting its critical functional role in hydrogenation, hydrodesulphurization, oxidative hydroxylation, reduction; CO conversion; fuel production; metalloges; hydrogenolysis; soot conversion; NOx conversion; drug delivery; methanation; esterification; transesterification; polymerization; oxidation; dry and stream reforming; as well as its use in the synthesis of different heterocyclic compounds. Hence, this review describes the increasing importance of citric acid as a catalyst by providing information on its mechanisms, uses, and potential for promoting environmentally friendly synthetic processes in the future.</p> Graphical abstract <p></p>