Plastics have become an indispensable component of modern society, with the unparalleled merits of cost-effectiveness, portability, durability, and versatility. However, the escalating accumulation of plastic waste is exacerbating a global pollution crisis. In recent years, upcycling plastics has emerged as a crucial strategy to address this crisis, not only offering a sustainable solution to mitigate environmental pollution but also converting plastic waste into high-value-added products. Photocatalytic technology, harnessing solar energy as the sole energy source to drive the upcycling of plastics, holds promise for clean energy storage, simultaneous resource sustainability, and environmental remediation under energy-neutral conditions. This paper provides a concise overview of the history of photocatalysis for plastic conversion, analyzes the mechanism of the photocatalytic degradation of plastics as well as the photocatalytic upcycling in both heterogeneous and homogeneous phases. Then, it focuses on the recent progress in applying photocatalysis to upcycle plastic wastes in two phases through different pathways. Finally, the challenges and opportunities of plastic photocatalytic upcycling are discussed in terms of the rational design and optimization of the catalytic system, mechanistic investigation, practical application, and the coupling of photocatalysis. It aims to offer insights and references to promote the industrial application of photocatalytic technology for plastic upcycling and to develop more eco-friendly, more cost-effective, and sustainable plastic upcycling technologies.