Academic freedom is under threat across the globe and a wave of substantial academic freedom declines affects not only autocracies but also (liberal) democracies. However, although the development of academic freedom has generated scholarly attention, this article presents the first systematic conceptualization and measurement of academic freedom growth and decline episodes. In particular, this article systematically analyzes the development of academic freedom across the globe and shows that global development follows waves of growth and decline. The first growth wave started in the mid-1940s and was succeeded by a second growth wave that started around 1977 and lasted for more than 30 years resulting in the greatest improvement in academic freedom that has been recorded since 1900. However, since 2013, we see an ongoing decline wave in academic freedom. Overall, this article highlights how academic freedom developed over time and across the globe in waves of growth and decline.