<p>The increasing harm to the environment from synthetic plastics has increased the need for sustainable alternatives, resulting in increased interest in biopolymers such as polyhydroxyalkanoates (PHAs). PHAs have the potential to serve as an alternative plastic derived from petrochemicals. This eco-friendly plastic is produced through microbial fermentation using various carbon sources. Since the cost of PHA production is significantly influenced by the carbon source, researchers are currently exploring cost-effective and more sustainable alternatives to conventional sugar-based feedstocks, including waste lipid streams such as waste cooking oil (WCO). WCOs have been demonstrated to be an excellent carbon source for the production of PHAs. WCOs are vegetable oils discarded after the food frying process and accumulate in larger quantities. Its management is a challenge due to the environmental risk of illegal disposal into rivers and landfills. The individual arrangement of biodegradability and biocompatibility, along with mechanical and thermal characteristics, makes PHA an excellent option for different uses, including paper coatings, films, packaging, adhesives, drug delivery, tissue engineering, and the development of artificial organs in the medical field. In this review we have discussed the potential use of WCO in the microbial fermentation of PHA production and its industrial applications.</p>