As in the web and desktop software, most app developers rely on third-party components —e.g., libraries or software development kits (SDKs)—that they integrate into their apps to add particular desired functionalities. This project aims to bring light to the issues and challenges that third-party SDKs bring to the mobile ecosystem, from a privacy, transparency and regulatory compliance standpoint. We conclude with a series of recommendations—applicable to different stakeholders—that could contribute to mitigate the privacy risks associated with third-party SDKs embedded in mobile applications.