Abstract: The development, deployment, and use of artificial intelligence (AI) systems and AI-based technologies are governed by an increasingly complex set of legal, ethical, social, and other types of norms, which surface from various sources and contribute to what might be described as a patchwork of norms. Among this complicated landscape of modes of governance, this chapter zeroes in on the extent to which professional norms — and specifically norms in the development phase as expressed in formal documents such as code of ethics and ethical principles — may serve as a reservoir of norms and accountability mechanisms to include within the existing governance toolbox. It explores the interface between AI and “the profession,” with an emphasis on new institutional arrangements and sources of norms that arise within the profession, such as corporate principles and employee demands. This chapter discusses trends of this fluctuating ecosystem through a suggested analytical framework for thinking about these professional norms of AI development within the broader context of the AI lifecycle, and hypothesizing about the future possibilities of professional norms within discussions of AI governance. A shorter version of this paper is forthcoming in: Markus D. Dubber, Frank Pasquale, and Sunit Das (eds.), The Oxford Handbook of Ethics of AI, Oxford University Press.