With regard to open science developments, scientometrics might play an important role. Scientometrics enable displays of changes in research practices and possibly measurements of the impact of open science initiatives. Conversely, metrics influence researchers’ practices and might be applied to achieve a widespread adoption of open science practices. This chapter discusses open science initiatives and goals, the establishment of policies and influences on researchers’ practices. With regard to these developments, metrics will be discussed as an evaluation tool for open practices on the one hand, and as an incentive to foster open science on the other. The last part of the chapter refers to the openness of metric analyses.