The ubiquity of microplastics in the environment is an emerging concern. These small plastics (<5 mm) along with associated contaminants may be consumed by organisms including humans and have been found in every environment on Earth. There are numerous data gaps about the potential effects of microplastics on human health and ecological systems. This presentation provides an overview of microplastics, the challenges of microplastic science, and the research conducted at EPA helping to fill the data gaps including understanding fate and transport, identifying toxicity, and advancing sampling and analytical methods. The webinar will also cover the Interstate Technology & Regulatory Council (ITRC) microplastics resources, including the Microplastics Outreach Toolkit.