We propose six challenges in evaluating mobile learning: capturing and analyzing learning in context and across contexts, measuring mobile learning processes and outcomes, respecting learner/participant privacy, assessing mobile technology utility and usability, considering the wider organizational and socio-cultural context of learning, and assessing in/formality. A three-level framework for evaluating mobile learning is proposed, comprising a micro level concerned with usability, a meso level concerned with the learning experience, and a macro level concerned with integration within existing educational and organizational contexts. The article concludes with a discussion of how the framework meets the evaluation challenges and with suggestions for further extensions.