Using six waves of the Schools and Staffing Survey and the National Teacher and Principal Survey that span two decades, our study explores the differences between urban charter and traditional public school teachers and how those differences become more or less pronounced over time. During this time frame, the charter sector experienced substantial growth and this growth could have the effect of making charter schools more like traditional public schools. We find that charter school teachers are different from their traditional public school counterparts in both their personal characteristics and working conditions, but grow more similar in their satisfaction/commitment and turnover.