Citizen science is an important way of engaging a broad range of audiences in science inquiry by participating in research that asks novel questions and unearths new knowledge and new questioning. Though citizen science projects are quite diverse in their scientific pursuits, all projects share the common element of involving volunteers directly in some aspect of science inquiry. Thus, it is essential for citizen science projects to determine their participants’ capacity to learn and successfully perform science inquiry skills, such as making scientific observations, collecting and analyzing data, and sharing findings. Such skill gains are essential to (a) ensure high quality data that can be used in meaningful scientific research, and (b) achieve broader goals such as developing a participant’s identity as a contributor to science. However, we do not yet fully understand how improvement in participants’ inquiry skills through citizen science advances our knowledge of public engagement with science. In this essay, we offer embedded assessment as an effective method to capture participant skill gains, and encourage citizen science leaders, evaluators, and researchers to develop authentic methods that address the complexities of measuring skill development within the context of citizen science.