Critical digital literacy (CDL) is a convergence of both digital and critical literacies. It encompasses the skills and competencies required to critically engage with digital media and technologies. It goes beyond basic digital literacy, i.e. the ability to use digital tools and platforms, and foregrounds critical thinking, analysis, and evaluation in digital contexts. In recent years, its scope has broadened to include awareness of how power operates in digital spaces and how this relates to how knowledge, identities, and social relations are shaped in ways that privilege some and marginalise others (Darvin R, Language, ideology, and critical digital literacy. In: Thorne S, May S (eds) Language education and technology, encyclopedia of language and education, vol 9. Springer, pp 17–30, 2017). With the arrival of generative AI, the remit of CDL has widened even further to include critical AI literacy, framed as a subset of CDL skills and concerned with bias and perpetuation of epistemological injustices through large language models (LLMs). Engaging with CDL, then, can help us understand how technologies are used in situated and encultured ways (Darvin R, Language, ideology, and critical digital literacy. In: Thorne S, May S (eds) Language education and technology, encyclopedia of language and education, vol 9. Springer, pp 17–30, 2017), akin to what Thorne (Lang Learn Technol 7(2):38–67, 2003, Lang Learn Technol 20(2):185–191, 2016) refers to as cultures-of-use in CALL contexts. This entry considers the nuances and implications of different conceptualisations of CDL including, most recently, the leveraging of digital technologies for social justice-oriented action and change (Jiang L, Gu MM, TESOL Q 56(3):1029–1040, 2022), which intersects with critical approaches to CALL.