This book constitutes the refereed proceedings of the 12th International Development Informatics Association Conference, IDIA 2022, held in Mbombela, South Africa, in November 2022. The 20 revised full papers presented in this volume were carefully reviewed and selected from 61 submissions. The papers are organized in topical sections on theories and practices in digital-for-development ecosystems; emerging technologies for transformation, inclusion and sustainable development; privacy and security in digital-for-development ecosystems; human-computer interaction (HCI) for digital inclusion; artificial intelligence (AI) for good.