Self-assembled monolayers (SAMs) on gold derived from the direct adsorption of thioacetic acid S-decyl ester (C10SAc) and thioacetic acid S-octadecyl ester (C18SAc) were compared to the corresponding SAMs derived from the analogous adsorption n-decanethiol (C10SH) and n-octadecanethiol (C18SH). All SAMs were characterized using ellipsometry, contact angle goniometry, polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS). The comparison revealed that the SAMs generated from the thioacetates are not as densely packed and well ordered as the SAMs generated from the thiols. Furthermore, studies of the kinetics of adsorption found that the thioacetates adsorb more slowly than the corresponding thiols.