Curricular integration in formal teaching of citizen science can bring to the classroom aspects of scientific literacy that encourage the involvement of citizens. In particular, these include non-epistemic aspects related to the sociology of science (which are often not transferred to the classroom). Furthermore, this practice raises awareness among students, and encourages them to become participants in the attainment of the United Nations’ Sustainable Development Goals (SDGs). This article describes a proposal for the integration of a citizen science project into the secondary education curriculum that can be reproduced in any educational center. Eighty-three secondary school pupils (14–15 years old) took part in this research at a city-center school in Northern Spain. A questionnaire based on validated studies was created and used to analyze the changes in attitudes of pupils towards science and technology and their improvement in scientific literacy in terms of scientific processes and scientific situations. The results indicate a significant improvement in the attitudes towards science and technology among the participating learners, as well as a better understanding of scientific processes and situations. Likewise, the results reflect how the implementation of the citizen science project contributes to the SDGs.