Interaction forces between glass surfaces with covalently attached quaternary ammonium groups (XNm, m is the carbon number of alkyl chains) in aqueous ionic surfactant solutions have been studied by the colloidal probe atomic force microscopy. Surface preparation of glass substrates was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angles. In the absence of surfactants, almost zero forces were observed between XN12 and XN16 glass surfaces, respectively, while in the case of XN8 an electrostatic repulsive force could be detected. By the addition of surfactants, dodecyltrimethylammonium chloride (DTAC) and/or sodium dodecyl sulfate (SDS), the electrostatic repulsion was observed above the half critical micelle concentration of each surfactant. In addition, with increasing concentration of the surfactants, the magnitude of force curves increased and the range of repulsion extended. These results suggest that the headgroups of adsorbed surfactants orient toward the solution phase and the charging-up mechanism is supported in these systems. On the other hand, the range of repulsion between XN16 glass surfaces in the surfactant solutions was not always larger than that between the other samples (XN8 or XN12) because the grafted alkyl chains onto glass can adopt various conformations corresponding to their chain length.