The Royal Institute of Philosophy volume of which this paper is an introduction is on the theme of ‘Expanding Horizons’. But what does it mean for philosophy to fruitfully expand its horizons? The contributions to the volume suggest at least five profitable ways. First, by looking to other philosophical traditions for new perspectives on familiar questions and alternative methods, questions, and ways of understanding. Second, by looking to what has been neglected or overlooked in our own histories of thought. Third, by developing novel methods, in addition to argument, for investigating philosophical issues. Fourth, by embracing different modalities for doing philology, such as the literary. Fifth, by reflecting on the practice of comparative philosophy to better understand the extent to which philosophy can and should be universal. Together, these approaches both increase the range of voices heard in philosophy and the scope and ambition of the discipline.