Carl Ransom Rogers (January 8, 1902 – February 4, 1987) was an American psychologist who was one of the founders of humanistic psychology and was known especially for his person-centered psychotherapy. Rogers is widely considered one of the founding fathers of psychotherapy research and was honored for his research with the Award for Distinguished Scientific Contributions by the American Psychological Association (APA) in 1956.

The person-centered approach, Rogers's approach to understanding personality and human relationships, found wide application in various domains, such as psychotherapy and counseling (client-centered therapy), education (student-centered learning), organizations, and other group settings. For his professional work he received the Award for Distinguished Professional Contributions to Psychology from the APA in 1972. In a study by Steven J. Haggbloom and colleagues using six criteria such as citations and recognition, Rogers was found to be the sixth most eminent psychologist of the 20th century and second, among clinical psychologists, only to Sigmund Freud. Based on a 1982 survey of 422 respondents of U.S. and Canadian psychologists, he was considered the most influential psychotherapist in history (Freud ranked third).

Rogers was born on January 8, 1902, in Oak Park, Illinois, a suburb of Chicago. His father, Walter A. Rogers, was a civil engineer and a Congregationalist by religious denomination. His mother, Julia M. Cushing, was a homemaker and devout Baptist. Carl was the fourth of their six children.

Rogers could read well before kindergarten. After being raised in a strict religious environment as an altar boy at the vicarage of Jimpley, he became isolated, independent, and disciplined, gaining knowledge and an appreciation for the scientific method in a practical world. At the University of Wisconsin–Madison, he joined the fraternity Alpha Kappa Lambda and initially planned to study agriculture before switching to history and finally settling on religion.

At age 20, following his 1922 trip to Beijing, China, for an international Christian conference, Rogers started to doubt his religious convictions. To help him clarify his career choice, he attended a seminar entitled "Why Am I Entering the Ministry?" after which he decided to change careers. In 1924, he graduated from the University of Wisconsin, married fellow Wisconsin student and Oak Park resident Helen Elliott, and enrolled at Union Theological Seminary in New York City. Sometime later, he reportedly became an atheist. Although referred to as an atheist early in his career, Rogers was eventually described as an agnostic. He reportedly spoke about spirituality quite often in his later years. Brian Thorne, who knew and collaborated with Rogers throughout the latter's final decade of life, writes: "In his later years his openness to experience compelled him to acknowledge the existence of a dimension to which he attached such adjectives as mystical, spiritual, and transcendental". Rogers concluded that there is a realm "beyond" scientific psychology—a realm he came to prize as "the indescribable, the spiritual."

After two years at Union, Rogers left to attend Teachers College, Columbia University, obtaining an M.A. in 1927 and a Ph.D. in 1931. While completing his doctoral work, he engaged in scientific studies of children. As an intern in 1927–1928 at the now-defunct Institute for Child Guidance in New York, Rogers studied with psychologist Alfred Adler. Later in life, Rogers recalled:

Accustomed as I was to the rather rigid Freudian approach of the Institute—seventy-five-page case histories, and exhaustive batteries of tests before even thinking of "treating" a child—I was shocked by Dr. Adler's very direct and deceptively simple manner of immediately relating to the child and the parent. It took me some time to realize how much I had learned from him.

In 1930, Rogers served as director of the Society for the Prevention of Cruelty to Children in Rochester, New York. From 1935 to 1940, he lectured at the University of Rochester and wrote The Clinical Treatment of the Problem Child (1939), based on his experience in working with troubled children. He was strongly influenced in constructing his client-centered approach by the post-Freudian psychotherapeutic practice of Otto Rank, especially as embodied in the work of Rank's disciple: noted clinician and social work educator Jessie Taft. In 1940, Rogers became professor of clinical psychology at Ohio State University, where he wrote his second book, Counseling and Psychotherapy (1942). In it, Rogers suggests that by establishing a relationship with an understanding, accepting therapist, a client can resolve difficulties and gain the insight necessary to restructure their life.