Backbone cyclization has a profound impact on the biological activity and thermal and proteolytic stability of proteins and peptides. Chemical methods for cyclization are not always feasible, especially for large peptides or proteins. Recombinant Staphylococcus aureus sortase A shows potential as a new tool for the cyclization of both proteins and peptides. In this review, the scope and background of the sortase-mediated cyclization are discussed. High efficiency, versatility, and easy access make sortase A a promising cyclization tool, both for recombinant and chemo-enzymatic production methods.