Four kinds of molecularly thin films of room temperature ionic liquids (RTILs) with different functional cations were prepared on silicon substrates by dip-coatingmethod. Thermal stability of the RTILswas evaluated using Mettler thermal gravity analysis (TGA) in a nitrogen atmosphere. Chemical compositions of the RTIL nanofilms were examined by means ofmultifunctional XPS. Nanoscaled adhesion and friction forces between the films andAFMtip were measured byFFMwhereas themorphologies of the films were also investigated. Microscaled friction and wear behaviors between the films and Si3N4 ball were further measured by the microtribometer. The micro/nanotribological behaviors of different RTIL films were comparatively investigated and discussedintermsoffunctionalcationsof theRTILsmolecules.Results in thispaperrevealedthatthefunctionalcationsoftheRTIL filmssignificantly affected their tribologicalbehaviorsbothinmicro-andnanoscales.Thecorrespondingmicro/nanotribological mechanism of the tested ultrathin RTIL films under the test conditions was consequently proposed based on the experimental results