The history of Psychology in the University of Santo Tomas started in 1645. It was then a part of the curriculum of Philosophy. In 1926, a Department of Psychology was formed for the first time under the College of Education offering Elementary Psychology. In 1932, Clinical Psychology was offered in the third year medicine proper in the Faculty of Medicine and Surgery. When Fr. Angel de Blas completed his Ph.D. at the University of Santo Tomas in 1934, he introduced new methods and devices in the fields of Zoology, Physics, and most especially in the field of Psychology. In fact, he established in 1938 the first laboratory in Experimental Psychology in the Philippines with his colleagues. The laboratory instruments used then were audiometer, anaesthesiometer, pain-pressure balance and other devices. The Experimental Psychology laboratory in UST was considered as the only one of its kind in Far East Asia at that time. 

Subsequently, in 1948, the College of Liberal Arts, which is now known as the College of Science, offered B.S. Major in Psychology. This course was offered for the first time in UST. The University of Santo Tomas was regarded as the first school in the Philippines to offer B.S. Major in Psychology with Fr. Angel de Blas, O.P. as the first Chairman of the Department of Psychology. From then on, Psychology as a science has undergone tremendous growth and success. 

In October 1994, the degree program was renamed as Bachelor of Science in Psychology. In 2011, the program received the highest accreditation–Level IV–from the Philippine Association of Colleges and Universities Commission on Accreditation (PACUCOA). The Department of Psychology was declared Center of Development in 2012 and Center of Excellence in 2016 by the Commission on Higher Education. The Professional Regulation Commission recognized the Department of Psychology as the only Top Performing School in the 2014 Psychometrician Licensure examinations, which UST graduates have performed well in since 2014. It is also a university-wide service department for various psychology-related general education courses. 

Added to this list of accolades is the program’s first international stamp of approval: the ASEAN University Network Quality Assurance (AUN-QA) certification, which was received in 2017.