This book offers the first integrated account of how psychological assessment has taken shape across Ibero-America by presenting country by country analyses of the development of the field in Argentina, Bolivia, Brazil, Chile, Costa Rica, Ecuador, El Salvador, Guatemala, Mexico, Paraguay, Peru, Spain, Uruguay and Venezuela. It traces institutional milestones, degree programs, and professional regulation, clarifying how psychodiagnosis, psychometrics, test adaptation, and ethical frameworks have evolved within diverse educational, clinical, occupational, and forensic settings. Written by leading scholars and practitioners, the volume synthesizes historical trajectories—from early laboratories and guidance institutes to contemporary commissions and societies—while examining persistent obstacles such as reliance on foreign instruments, uneven standardization, and access to materials. The chapters foreground reliability, validity, consequential validity, and responsible test use; they review cross cultural adaptation practices, item response theory, computerized adaptive testing, and ecological momentary assessment, alongside the roles of national councils, colleges of psychologists, and international bodies in improving test quality and governance. Beyond documenting achievements, Origins and Challenges of Psychological Assessment in Ibero-American Countries delineates pragmatic pathways for strengthening assessment through research networks, indexed publication, and transparent quality criteria to support evidence based diagnosis and intervention. Its balanced scope—historical, methodological, and policy oriented—makes it a timely reference for students, academics, and professionals seeking rigorous, context aware assessment in Latin America and Spain. This is an English edition of a book originally published in Spanish. The translation from Spanish into English was done with the help of artificial intelligence. A subsequent human revision was done primarily in terms of content.