In 2009, Florida adopted its Differentiated Accountability (DA) plan, the first accountability policy that specifically takes into account rigorous coursetaking and college readiness targets, in addition to the traditional benchmarks on standardized tests and graduation rates.  These changes were in part spurred by calls from federal policymakers and national organizations (for example, Education Trust, National Governors Association, Achieve, Inc.,) to increase the rigor of coursework that high school students take that would lead to college and career readiness.  In this paper we use a rich panel of high school students in Broward County Public Schools from 2000-01 through 2012-13 to present the early evidence of the impact of high school accountability on students’ academic coursetaking, including advanced coursetaking, and students’ likelihood of graduating high school within four years of entry.  Further, we explore whether or not the impact depends on the quality of the school as measured by school grades awarded under the accountability systems and if the effects differ for sub-groups of students (e.g., socio-economic status, race/ethnicity).  Using a difference-in-difference approach, we estimate the impact of DA on a series of coursetaking indicators and trajectories as well as likelihood of graduating within four years, controlling for student demographic and socio-economic characteristics, educational need, prior achievement and disciplinary records that may serve as a proxy for attitudes and motivation that will help us account for unobservable heterogeneities across students.  Our preliminary findings that are based on a shorter panel that goes through 2010-11 (thus, only two post-years) do suggest that DA increases students likelihood of taking math courses in a timely manner that aligns with college readiness standards (e.g., Geometry in 10^th grade, Algebra II or higher in 11^th grade).  While we find some evidence that DA increases overall participation in AP tests, but little evidence of any impact on test results.  The impact on participation in AP tests is strong, especially for minority and low-income students and in low-performing schools.  The performance gains on AP tests are concentrated among white students in high-performing schools.  As we add two years of post data, bringing the total to four post years, we will test to see if these effects hold.  Also, we will be extending our analysis to include the outcomes listed above (e.g., likelihood of graduating within four years).