The 2006-2007 school year was the eighth annual reporting period since disaggregating the performance of students with disabilities on state and district-wide assessments was required by the Individuals with Disabilities Education Act (IDEA). It is the fifth reporting period since the enactment of the No Child Left Behind Act (NCLB), and the eleventh in a series of National Center on Educational Outcomes (NCEO) reports documenting state public reporting practices. Historically, the number of states publicly reporting disaggregated participation and performance data for all regular assessments has increased from 28 states before the passage of NCLB (2000-2001), to 39 states for assessments within NCLB accountability systems in 2005-2006. In the intervening years, the number has fluctuated some, from 36, 35, and 36 in 2002-2003, 2003-2004, and 2004-2005, respectively. The number of states reporting disaggregated participation and performance data for all alternate assessments had decreased from the high reported in 2004-2005 of 42 states to 28 states in 2005-2006. This change in reporting may be related to changes in federal policies for reporting to the U.S. Department of Education and to the authors' procedures, in which they did not count Annual Performance Report (APR) data as publicly reported data. Nine appendices are included: (1) Sample Letter Sent to Assessment Directors; (2) Sample Letter Sent to Special Education Directors; (3) Status of Disaggregated Data (Participation and Performance) for Students with Disabilities on Regular State Tests in the Fifty States and Unique States for 2006-2007; (4) Status of Disaggregated Data (Participation and Performance) for Students with Disabilities on Alternate State Tests in the Fifty States and Unique States for 2006-2007; (5) Disaggregated Participation Information for Students with Disabilities on Regular State Tests for the Fifty States and Unique States for 2006-2007; (6) Disaggregated Alternate Assessment Participation Information for Students with Disabilities on Regular State Tests for the Fifty States and Unique States for 2006-2007; (7) Disaggregated Regular Assessment Performance Information for Students with Disabilities for the Fifty States and Unique States for 2006-2007; (8) Disaggregated Alternate Assessment Performance Information for Students with Disabilities for the Fifty States and Unique States for 2006-2007; and (9) Participation and Performance for Students Tested with Accommodations. (Contains 30 figures and 12 tables.)