The charter school movement is premised on the idea that, if independent operators create differentiated and innovative schooling options, families will benefit from making meaningful choices among those options that reflect their preferences. Charters are freed from many of the constraints traditional public schools face, allowing them to implement distinct academic models, school cultures, or curricular focuses that appeal to a subset of families. The consistent growth of charter schools, which now constitute one in 14 public schools nationwide, provides some evidence of the popularity of these options. However, it has been difficult to gauge how much differentiation there is in charter school models nationwide and how substantive it is. This paper attempts to shed light on these questions. Looking at charter schools across the nation, the authors use the content on charter schools' websites to identify their academic models. Nearly half of charter schools had a specialized academic model, and these were further divided into a dozen specific categories. These nonexclusive categories included no-excuses schools, schools focused on arts or STEM (Science, Technology, Engineering, and Mathematics) education, and schools focused on vocational education.