Clark Wissler (September 18, 1870 – August 25, 1947) was an American anthropologist.

Born near Hagerstown, Indiana, Wissler graduated from Indiana University in 1897. He received his doctorate in psychology from Columbia University in 1901. After Columbia, Wissler left the field of psychology to focus on Anthropology. Clark Wissler worked at the American Museum of Natural History as a Curator in ethnology from 1902 to 1907. In 1907 Wissler was named Curator of Anthropology when the Archaeology and Ethnology departments were recombined under the Department of Anthropology. Clark Wissler was the first anthropologist to perceive the normative aspect of culture, to define it as learned behavior, and to describe it as a complex of ideas, all characteristics of culture that are today generally accepted. Wissler was a specialist in North American ethnography, focusing on the Indians of the Plains. He contributed to the culture area and age - area ideology of the diffusionist viewpoint that is no longer popular in anthropology. Ball State University in Muncie, Indiana, holds the archives of Clark Wissler. Furthermore, one hall of Indiana University's Teter Living Center is known as "Clark Wissler Hall".

Clark Wissler is a renowned American Anthropologist and Archaeologist who was born on September 18, 1870 in Wayne County, Indiana. After graduating from Hagerstown High School, he taught in local schools between 1887 – 1892, and studied at Purdue University after the six months school term ended. The following year in 1893 he was the principal of Hagerstown High School, and then he resigned his post and enrolled in Indiana University.

Wissler received his BA in Experimental Psychology in 1897 and received his MA in 1899. Wissler married Etta Viola Gebhart on June 14, 1899 and he fathered a son and a daughter, Stanley Gebhart Wissler and Mary Viola Wissler. In 1899 Wissler was appointed assistant in psychology at Columbia University. He continued his psychology graduate work under James McKeen Cattell and he received his Ph.D. in psychology in 1901. From 1901 to 1903 Wissler performed research on individual mental and physical differences. Wissler's doctoral dissertation used the new Pearson Correlation Coefficient formula to show that there was no correlation between scores on Cattell's IQ tests and academic achievement. Wissler's dissertation eventually led the psychology movement to lose interest in psychophysical testing of intelligence.

When Wissler graduated from Columbia he abandoned psychology for anthropology. In 1902 he became an assistant in Ethnology at the American Museum of Natural History under Franz Boas. In 1904, Wissler was named assistant curator of Ethnology and in 1905, when Boas resigned, Wissler was named Acting Curator of Ethnology. The following year of 1906, he was named curator of the Department of Ethnology and in 1907 he was named curator of Anthropology when the Archaeology and Ethnology departments were recombined under the Department of Anthropology. In 1924 Wissler began teaching at Yale University as a Psychological Researcher until 1931 when he switched to an Anthropology Professor, which he held until 1941. Wissler held the position of Curator of the Department of Anthropology until 1942 when he retired.

Clark Wissler performed his field research from 1902 until 1905 on the Dakota, Gros Ventre, and the Blackfoot. Wissler's fieldwork provided comprehensive ethnographies of each Native American culture, especially the Blackfoot. While Curator, Wissler funded ethnological and archaeological fieldwork of the Northern Plains and the Southwest. Wissler also "encouraged physical anthropology, built up collections of worldwide scope, planned exhibitions, and oversaw the publication of about thirty eight volumes of the Anthropological Papers of the American Museum of Natural History."

Wissler's best contribution to anthropology is his Culture - Area Approach. "He was the first anthropologist to perceive the normative aspect of culture, to define it as learned behavior, and to describe it as a complex of ideas, all characteristics of culture that are today generally accepted." Wissler wanted to compare different cultures, but in order to do that he first needed to define what a culture is. The concept of Culture Area had been around before Wissler, but he redefined the concept so it could be used analytically. Wissler revolutionized the study of culture to a theory of cultural change and as an alternative to the Boasian style of anthropology. Wissler shifted the analytical focus away from the culture and history of a specific social unit to "a concern with the trait - complex viewed in cross cultural perspective." "The correspondence of a well defined geographical area with a group of cultures that share many features is the basis of the concept of the culture area." Wissler states that the principal barriers that preserve the distinctness of a culture area as physical: surface, climate fauna, and flora. Wissler was trying to make cultural anthropology more scientific by forming a definition of culture that could be used to compare similar or different cultures. With a set of parameters for what a culture can be based upon, variables such as climate, environment, resources, food, water, and population size etc., researchers could now compare their studies of Plains Indians to their studies of Great Basin Indians. Wissler also helped introduce statistics with the Pearson Correlation Coefficient Formula which could be used to compare different artifacts in relations to their geological location. This could help understand where a certain artifact, piece of pottery, or type of tool originated by testing if there is a high correlation of a certain artifact with sites in certain areas.

Clark Wissler's main area of research was on Native American Culture. His influence is overlooked because of other anthropologists like Franz Boas and Ruth Benedict. Wissler offered some new theories that were quite different from Boas, who was a leading Cultural Researcher. One of Wissler's new concepts was the belief in cultural diffusion and that culture was biologically innate in humans. "Wissler also came up with the age - area hypothesis that is a theory that the age of cultural traits may be determined by examining the distribution of these traits throughout the larger area where these traits are present." Wissler's Influence is still felt in Anthropology today and he is credited for helping make Cultural Anthropology and Psychology more scientific with analytical and statistical testing.