Issues related to the evolving role of citizen science and open science are reviewed and discussed in this article. We focus on the changing approaches to science, research and development related to the turn to openness and transparency, which has made science more open and inclusive, even for non-researchers. Reproducible and collaborative research, which is driven by the open access principles, involves citizens in many research fields. The article shows how international support is pushing citizen science forward, and how citizens’ involvement is becoming more important. A basic scientometric analysis (based on the Web of Science Core Collection as the source of peer reviewed articles) provides a first insight into the diffusion of the citizen science concept in the field of Geography, mapping the growth of citizen science articles over time, the spectrum of geographical journals that publish them, and their citation rate compared to other scientific disciplines. The authors also discuss future challenges of citizen science and its potential, which for the time being seems to be not fully utilized in some fields, including geographical research.