In this article, we highlight why and how industrial and organizational psychologists can take advantage of research on 21st century skills and their assessment. We present vital theoretical perspectives, a suitable framework for assessment, and exemplary instruments with a focus on advances in the assessment of human capital. Specifically, complex problem solving (CPS) and collaborative problem solving (ColPS) are two transversal skills (i.e., skills that span multiple domains) that are generally considered critical in the 21st century workplace. The assessment of these skills in education has linked fundamental research with practical applicability and has provided a useful template for workplace assessment. Both CPS and ColPS capture the interaction of individuals with problems that require the active acquisition and application of knowledge in individual or group settings. To ignite a discussion in industrial and organizational psychology, we discuss advances in the assessment of CPS and ColPS and propose ways to move beyond the current state of the art in assessing job-related skills.