Microplastic (MP) pollution has emerged as a critical concern in the marine environment, with ship-generated wastewater identified as a significant but understudied source. Literature review synthesises current knowledge on the presence of MPs in shipboard wastewater, focusing particularly on greywater, which remains unregulated under the existing MARPOL 73/78 Annex IV. The reviewed literature demonstrates that most currently used wastewater treatment systems are not explicitly designed for MP retention, facilitating the continued emission of MPs particles into the aquatic environment. The review evaluates existing and emerging MP removal technologies, drawing on municipal and industrial wastewater treatment practices, such as membrane bioreactors, disc filters, sand filtration, hydro cyclones, and advanced adsorption systems, including magnetic carbon nanotubes, which demonstrate high removal efficiencies under controlled conditions. However, the integration of such systems into shipboard treatment plants remains limited due to technical and operational challenges. Recent pilot installations of MP collectors in ballast and cooling water systems signal a potential pathway for maritime adaptation. The findings underscore the need to update international regulatory frameworks and to promote the development of compact, low-energy, and modular treatment technologies suited for maritime sewage treatment plants.