We have studied the early stages of Ag electrodeposition from dilute sulfuric acid solutions on modified Au(111) electrodes with cyclic voltammetry and in situ scanning tunneling microscopy. Several differently functionalized short-, medium-, and long-chain alkanethiols were used for electrode modification. Ag underpotential deposition onto such surfaces is hindered depending on chain length, but the differences between self-assembled monolayers with different endgroups were less significant. Two Ag layers are deposited at the thiol/Au(111) interface in an island growth mechanism at underpotentials. Bulk deposition originates almost exclusively at step edges burying the underlying self-assembled monolayer. Oxidative desorption of the organic film is promoted in contact with a Ag + -containing electrolyte as compared to the metal ion free solution.