Folding apparatus (1) for folding sheet packaging elements (2), comprising main conveying means (12), configured to sequentially receive the packaging elements (2) from a feeding station (13) and to advance each packaging element (2) along a first path (A), forming means (15), carried by the main conveying means (12) and configured to cooperate in use with a first face (2b) of each packaging element (2) while the packaging element (2) is advanced along the first path (A), and folding means (18), advanced by auxiliary conveying means (16) along a second path (Q), having a first portion (Q1) distinct from the first path (A) and a second portion (Q2), which is in common with the first path (A) and along which the folding means (18) cooperate with a second face (2a), opposite the first face (2b), of each packaging element (2) to fold the packaging element (2) against the forming means (15).