This yearlong qualitative study is an examination of 10 undergraduate preservice teachers' lesson planning for the classes and/or individual lessons they taught in a university string project. Data analysis revealed that these preservice teachers held differing views of lesson planning from each other and from their supervisor. Five themes emerged: (a) concerns about knowing how to begin to plan, (b) difficulty identifying what the children needed to learn, (c) the prominence of decisions made on the fly, (d) comparisons of thinking about teaching and planning with actual written plans, and (e) limited transfer of in-class experiences to teaching in the project. Suggestions for teacher educators include acknowledging the complex nonlinear relationship between planning skills, teaching experience, and professional knowledge; structuring guided experiences with a variety of lesson planning formats (e.g., written, mental, verbal); and maximizing opportunities for preservice teachers to reflect on connections between their experiences as students and as teachers.