Health technology assessment (HTA) has assumed an increasing role in health systems in recent years, with many countries establishing agencies or programmes to evaluate health technology and other interventions to inform policy decisions and clinical practice. This paper reflects upon its development and evolution in Europe over the last decade, with a focus on England, France, Germany and Sweden. In particular, we explore how HTA has evolved over time as well as its impact on policy and practice. While countries share many of the same objectives, there are differences in the way HTA agencies and programmes are organised, operate, and influence decision making. Despite these differences, all systems are faced with opportunities and challenges related to stakeholder involvement and acceptance, the suitability and transparency of assessment requirements and methods, balancing evidence and values in decision making, and demonstrating impact.