Microplastic (MP) pollutants, defined as polymers smaller than 5 mm, are increasingly recognized as a widespread environmental concern. While their impacts are becoming clearer, the full extent of their consequences remains uncertain. MPs vary significantly in size and are prevalent in domestic sewage sludge (DSS), largely due to synthetic fibers from textiles and personal care products like toiletries and cosmetics. DSS is rich in organic matter, biomass, and inorganic chemicals, which complicates the extraction and identification of MPs. Proper characterization is essential for effective removal. Anaerobic digestion (AD), a leading treatment method for organic-rich sewage sludge, offers multiple benefits: biogas production, pathogen elimination, odor reduction, and sludge volume minimization. However, studies reveal mixed findings on how MPs influence AD, highlighting both potential benefits and challenges that remain poorly understood. Therefore, the present study aims to characterize microplastics using various methodologies and outlining sampling and extraction techniques for microplastics from sewage sludge. It also examines MPs’ degradation during AD and their behavior within sewage treatment systems. The study highlights that MPs are found universally in sewage sludge, varying in size, composition, and concentration, with polyethylene, nylon type and fibers/fragments being the most common. Removal efficiencies at wastewater treatment plants range from 93.8 to 99.8%, yet the regional and study-specific variations are significant. Traditional sewage sludge management methods, such as composting, landfilling, and agricultural applications, inadvertently reintroduce MPs into the environment. In agriculture, MPs alter soil properties, affecting microbial populations, plant health, and soil biota. Hence, it is essential to prevent MPs from impacting the environment and to exclude them from sewage sludge.