In the past, students with disabilities were frequently excluded from statewide testing. With changes in federal laws, states are seeking ways to increase the participation of students with disabilities in testing. Many have developed lists of allowable accommodations to facilitate participation. Although there has been an increase in research on how accommodations can aid in the measurement of skills among students with disabilities, many questions remain unanswered. The degree to which accommodations may compromise the integrity of tests is not clear. As a result, accommodation decision making is difficult. A review of research on 5 frequently allowed test accommodations (dictated response, large print, Braille, extended time, and sign language interpreter for instructions) was conducted; 36 studies were identified. Results indicate mixed support and nonsupport for providing these accommodations to students with disabilities. Guidelines for effective accommodation decision making and administration are discussed, and recommendations for future research are given.