We present an overview of recent developments in the fabrication and uses of colloidal crystals (CCs) for photonics and laser applications. Microparticles with a diameter in the range from 10 nm to 10 μm often have an intrinsic capability to spontaneously organize themselves from a colloidal suspension into 3D lattice structures. Such highly ordered 3D architectures of microparticles are called colloidal crystals (CCs). The CC structures have received tremendous attention as one of the facile and high‐throughput fabrication techniques of photonic crystals (PCs). We introduce here interesting precedents not only of diverse techniques of high‐quality CC structures, but also of their versatile applications in optical sensors responding to various external stimuli. This review also highlights a new potential use of the CCs as low‐threshold laser devices. We believe that a wide variety of CC architectures will play leading roles in the next generation of optoelectronic devices. An overview of recent developments in the fabrication and uses of colloidal crystals (CCs) for photonics and laser applications is presented. Microparticles with a diameter in the range from 10 nm to 10 µm often have an intrinsic capability to spontaneously organize themselves from a colloidal suspension into 3D lattice structures. The CC structures have received tremendous attention as one of the facile and high‐throughput fabrication techniques of photonic crystals. Examples are presented not only of diverse techniques of high‐quality CC structures, but also of their versatile applications in optical sensors responding to various external stimuli.