Immigrants now account for more than 115 million people in the OECD, which represents almost 10% of the total population. Their share has increased in virtually all OECD countries over the past decade, and children of immigrants are also entering the labour market in growing numbers. Against this backdrop, the integration of immigrants and their offspring has become a prime policy objective for OECD countries, and a vast array of different integration policies have been adopted over the past fifteen years. Among the various challenges for integration, perhaps the most important one is releasing the full skills potential of immigrants and their offspring. Skills of immigrants that are not used represent a wasted resource at a time when economies are increasingly less able to afford such waste, and may also impact negatively on social cohesion.The chapter takes stock of the broad issues involved in the labour market integration of immigrants and their offspring from a human capital perspective, as well as of the policies at hand to free their full skills potential through the identification and utilisation, the activation, and the development of their skills. It builds on the extensive work of the OECD on integration issues, together with new evidence. The chapter first identifies the main issues involved, followed by a discussion of the instruments and policies in OECD countries along the three pillars identified by the OECD Skills Strategy – namely using, developing and activating skills.