Ryan focuses his research on legal philosophy/jurisprudence, administrative law, medical law, and legal history. He also has sub-specialties in clinical research regulatory matters, bioethics, comparative health systems and policy, as well as the role of compliance and ethics programmes in corporations. He is affiliated with the Aquinas Institute at Blackfriars and has been a visiting fellow of the Anscombe Bioethics Centre. He also teaches Roman Law with an interest in its connections to medieval and contemporary law. His current projects include work in comparative administrative law as well as theories of regulation and the common good. His work in legal philosophy is rooted in English medieval law and Roman law. He is the Convener of Oxford's Common Good Project.