Abstract: Cosmological collider physics uses the high-energy spacetime background during cosmic inflation to probe new particles and interactions at high energy scales. Massive particles produced during inflation can leave characteristic oscillatory signals in the correlation functions of primordial perturbations, revealing information about their masses, spins, and interactions. This article introduces the basic physical picture of cosmological collider physics, including the production and evolution of massive particles and their interactions with curvature perturbations. It then reviews phenomenological applications involving the Standard Model and new physics, and briefly discusses recent developments in the study of cosmological amplitudes.