Officers of Parliament play a vital role in providing parliamentarians with access to critical information and resources that allow them to hold the government of the day to account. Critics have argued officers have exceeded their mandates and even threaten to supplant the opposition. Canada's Conflict of Interest and Ethics Commissioner (CIEC) holds a unique mandate, given that her primary focus concerns the behaviour of public office holders. This article draws on a comprehensive examination of the commissioner's reports and recommendations, and a content analysis of committee appearances to analyze and understand the impact and role of the CIEC. In contrast to the portrayal of other officers in the extant literature, we find that the office of the CIEC is constrained in its mandate and its impact limited by the nature and extent of its relationship with Parliament.