Single layer and multilayer polymer thin film (20-100 nanometer) coating on polymer substrate are gaining significant attention these days because of its wide range of applications. Optoelectronics, microelectronics, touch screen panels, wrinkled surfaces, stimuli-responsive films, polymer nanopillars for energy storage and contact lenses are some of the applications of these polymer thin films. In almost all of these thin films, the interface between the two films plays a major role in determining the overall performance of the coated system. Thus, the quantitative and qualitative estimation of interface response for thin film coating under different service conditions is significantly important from the perspective of modeling and designing of novel materials. Nanoindentation is one of the techniques which can be applied to characterize these interfaces. In this lecture, I will discuss about the fundamentals of nanoindentation; application of indentation in characterizing polymer-polymer interfaces of different strengths; the mechanism (such as pile-up) and challenges (such as substrate effect) involved in the characterization process. I will conclude with a discussion on how nanoindentation can be applied to generate polymeric nano-pillars of different shapes and sizes.