Dye-laden wastewater, characterized by its complex composition and persistency, poses a severe environmental risk. Conventional treatment methods are often ineffective in completely removing dye pollutants. This necessitates exploring sustainable alternatives to improve dye removal efficacy. Polyhydroxyalkanoates (PHAs) have emerged as a promising bio-based solution to this challenge. The unique properties of PHAs, including biodegradability, biocompatibility, and versatility, make them suitable for dye adsorption and biofilm carrier applications. This chapter explores the characteristics of dye wastewater, the conventional dye treatment methods and their limitations, as well as the potential of PHAs for dye treatment. The effectiveness of PHA and composites for dye adsorptions are discussed. Additionally, PHAs serve as excellent matrices for biofilm immobilization, facilitating the biodegradation of dyes. The feasibility of simultaneous dye biodegradation and PHA production is explored too. Despite their promising potential, the high PHA production cost, selectivity issues, and scalability limitations require further research and development.