This article explores the learning opportunities that standards-based portfolio assessment offers to promote teacher and faculty learning in teacher education. It discusses the impact on learning from two perspectives: that of teacher candidates and faculty using a paper-and-pencil approach for portfolio development, mentoring, and scoring; and from that of teacher candidates and faculty who used an electronic platform (UCOPIS) for portfolio development, mentoring, and scoring. The first section of the article reviews the empirical literature studying the impact of performance assessments on teacher learning and elucidates methodological difficulties in measuring teacher learning. The second section points to the opportunities and challenges that electronic applications may provide for measuring changes in teacher knowledge and skills and for enhancing teacher learning.