This paper reviews work on the second-order nonlinear optical properties of chiral thin films and surfaces. We give an overview of the theoretical formalism and experimental techniques to describe the second-harmonic generation (SHG) from chiral thin films and surfaces. We also discuss the second-harmonic response of thin films and surfaces composed of chiral synthetic materials and biological molecules. In addition, we point out possible applications and the future prospects in this field. (C) 2003 Elsevier B.V. All rights reserved.