The key to education reform lies in exploring alternative forms of assessment. Alternative performance assessments provide a more valid measure than multiple-choice tests of students' conceptual understanding and higher-level skills such as problem solving and inquiry. Advances in game-based and virtual environment technologies are creating new possibilities for learning and assessment. One such possibility is through the use of immersive 3D technologies that aim to situate students in an environment that promotes problem solving and inquiry and sets the context for assessment. This paper describes three on-going research projects that are using immersive 3D virtual environments as a platform in which to enable the summative, self-, and formative assessments of student learning.