This review gives an overview of the recent literature regarding lateral molecular interactions in monolayers. The first part (Section 3) focuses on systems of self-assembled monolayers on metal surfaces, discussing the covalent and noncovalent interactions of the terminal functionality or between the molecular chains of the molecules. The second part (Section 4) highlights the intermolecular interactions of monolayers on silicon and metal oxide surfaces. The third part (Section 5) presents examples of lateral interactions on receptor surfaces. A focus in all parts is on examples of lateral interactions in monolayers in which electron or energy transfer occurs.