Cutaneous bioavailability (BA) and bioequivalence (BE) study are important for developing and optimizing topical products applied to the skin, as well as evaluating products through regulatory processes. While a wide range of methods have been utilized for the study of BA and BE, optical microscopic imaging methods have the unique ability to noninvasively image skin, visualize the skin microstructure, and track active pharmaceutical ingredient (API) and excipients distributed in different skin regions and stratifications. In addition to tracking API permeation into the skin, optical microscopic imaging methods also enable characterization of API’s metamorphosis and understanding of effects on absorption. This chapter will focus on optical microscopic techniques that have been used in dermal drug absorption studies, including fluorescence imaging, infrared imaging, spontaneous Raman imaging, and coherent Raman imaging. Each technique has different features in terms of spatial resolution, in vivo imaging capabilities, imaging speed, imaging depth, and the need for labeling. The chapter begins by introducing the theory of each technique and the instrumentation needed for building these systems. Examples of each technique are reviewed to demonstrate their capabilities and potentials, and their limitations in evaluating dermal drugs. At the end of the chapter, current challenges and opportunities are discussed.