Polyurethane chemistry can yield diverse sets of polymeric materials exhibiting a widerange of properties for various applications and market segments. Utilizing lignin as a polyol presentsan opportunity to incorporate a currently underutilized renewable aromatic polymer into theseproducts. In this work, we will review the current state of technology for utilizing lignin as a polyolreplacement in different polyurethane products. This will include a discussion of lignin structure,diversity, and modification during chemical pulping and cellulosic biofuels processes, approachesfor lignin extraction, recovery, fractionation, and modification/functionalization. We will discussthe potential of incorporation of lignins into polyurethane products that include rigid and flexiblefoams, adhesives, coatings, and elastomers. Finally, we will discuss challenges in incorporating ligninin polyurethane formulations, potential solutions and approaches that have been taken to resolvethose issues.