This chapter explores the ethical and legal aspects of impact assessment in education, highlighting that methodological rigor alone is insufficient without consideration of rights, fairness, and transparency. It introduces a hierarchy of ethical principles—from dignity and autonomy to scientific integrity—forming the basis for trustworthy evaluations. The text applies these principles to educational dilemmas, such as dual consent with minors, stigmatization, and communicating results. It examines AI’s opportunities and risks, proposing frameworks of explainability, fairness, accountability, and human oversight. A comprehensive compliance framework is detailed, comprising legal regulations, institutional governance, and risk management. Four cases (the UK grading algorithm, DeepMind & NHS, PISA stigmatization, and the Dutch childcare scandal) demonstrate how violations can erode trust and lead to crises. The chapter concludes with principles for ethical impact evaluations that respect rights and improve validity, credibility, and social usefulness, stressing that ethics are essential for meaningful impact assessments.