An increasing number of knowledge brokers work at the interface between research, policy and practice. Their function is to facilitate processes to foster mutual learning among research, policy and practice. For some knowledge brokers, practical methodologies to assess the quality of their work is an important concern. While frameworks exist for assessing research impact at the level of a project or program, few are available for assessing contributions of individual knowledge brokers. In response to this, we have compiled a set of indicators to measure the quantity and quality of the contributions of individual knowledge brokers to projects, programs or platforms at the interface between research, policy and practice. The set is based on a review of the literature and the experience of a group of knowledge brokers active in water research and management in Switzerland, including the co-authors of this article. The set can be used by knowledge brokers to identify ways to improve the effectiveness of their practices and to demonstrate the benefit of their work to their employers and other stakeholders. Our approach is flexible enough that it can be applied where there are limited resources available for assessment.