The growing demand of sustainable and biocompatible optical devices is stimulating the development of naturally derived biomaterials for optics and photonics. As a versatile biomaterial, silk provides excellent material characteristics that are favorable towards the generation of advanced optical systems. This review examines the use of silk as a material platform in optical applications. Recent advances in silk-based optical devices and multifunctional devices are summarized. The challenges and directions in further designing and fabricating silk optics are also discussed. We envision that silk will play a pivotal role in the future exploitation of sustainable, intelligent, wearable/implantable, and multifunctional optical devices.