Thin films and coatings play a critical role in everything from food containers to photovoltaics. To meet such varied needs, they are made from every class of materials and by numerous processes, including deposition, self-assembly, and sol-gel techniques. Atomic force microscopy is a powerful tool for characterizing thin films and coatings, providing valuable information critical to performance. AFM quantifies 3D roughness and texture with unmatched spatial resolution, and measures nanoscale functionality including electrical, magnetic, and mechanical properties. The intrinsic dimensions of these films (thickness, grain and domain sizes, etc.) make it important to characterize them at sub-nanometer to micrometer resolutions. In addition, the ability to measure functional properties simultaneously at these length scales has become a key aspect of thin film engineering for targeted applications. AFM provides critical information in the development, optimization, and monitoring of thin film growth processes, and in rationalizing design pathways to achieve desired functional properties.