Halide perovskite semiconductors have emerged as promising candidates for the next-generation low-energy consumption, high-flexibility photonics and optoelectronic devices thanks to their superior optical and excitonic properties as well as fabrication convenience. This special issue, including three review papers and six original research papers, focuses on the studies of both fundamentals and applications of perovskite photonics, covering materials, excitonic properties, nonlinear optics, strong light–matter interactions, and optoelectronic devices.