Students with disabilities often take tests under different conditions than their peers do. Testing accommodations, which involve changes to test administration that maintain test content, include extending time limits, presenting written text through auditory means, and taking a test in a private room with fewer distractions. For some students with disabilities, accommodations such as these are necessary for fair assessment; without accommodations, invalid interpretations would be made on the basis of these students' scores. However, when misapplied, accommodations can also diminish fairness, introduce new sources of construct-irrelevant variance, and also lead to invalid interpretation of test scores. This module provides a psychometric framework for thinking about accommodations, and then explicates an accommodations decision-making framework that includes a variety of considerations. Problems with current accommodations practices are discussed, along with potential solutions and future directions. The module is accompanied by exercises allowing participants to apply their understanding.