This chapter explores the role, evolution, and effectiveness of a small but remarkable institution, the New Zealand Parliamentary Commissioner for the Environment (PCE). Established under the Environment Act 1986, the Commissioner’s primary functions are, put simply, to serve as an environmental guardian, an independent assessor of environmental policies, systems and processes, and a non-partisan advocate for sound environmental management. The mission is, to quote a recent Commissioner, ‘[t]o maintain or improve the quality of the New Zealand environment by providing robust independent advice that influences decisions’. While not a ‘commission for future generations’, to the extent that the PCE is able to promote the wise stewardship of resources, greater policy far-sightedness, and better environmental outcomes, both current and future generations stand to gain.