The accumulating piles of plastics have emerged to be among the greatest environmental issues across the world because of their inability to degrade, the low recycling rates, and non-biodegradability. Gasification has potential as a sustainable and technologically encouraging pathway towards converting plastic waste into useful energy carriers, and, in particular, synthesis gas, a mixture of hydrogen and carbon monoxide. As opposed to incineration, gasification is controlled with the oxygen conditions, which transforms the plastics into clean syngas with less emission and more energy efficiency. By facilitating the recovery of energy, reuse of resources, and the possibility of downstream generation of fuels and chemicals, this process promotes waste reduction as well as the objectives of the circular economy. The current paper is a review of the gasification of plastic waste, focusing on the mechanism of the process, reactor configuration, operating parameters, the composition of the syngas, and its environmental performance. It also addresses the concept of techno-economic viability and the results of life-cycle assessment and integration in the context of the circular economy. Even though there are still some challenges, such as tar formation, feedstock heterogeneity, and scalability, the improvement of catalytic reforming, co-gasification, and integration of renewable energy is improving the possibility of large-scale implementations. Gasification, therefore, is an important way forward in ensuring sustainable waste management and a low-carbon system of energy, which helps to not only protect the environment but also enhance economic strength.