Whenever sex differences occur in academic performance there is the possibility that these differences result, at least in part, from the sex biases and stereotypes in our society, including those presented by educational materials. McNemar noted this possibility over 30 years ago when he suggested that sex differences in performance on various Stanford-Binet items apt to be a function of the content of an rather than any basic ability called for by the item (McNemar, 1942, p. 42). Authors have defined sex bias and sex stereotyping in various ways. In this study, sex bias refers to use of a disproportionate number of references to either males or females, even when the content of the material does not demand such emphasis-e.g., the preponderance of masculine pronouns in textbooks. In contrast, sex stereotyping will be used to refer to conventional, rigid, oversimplified presentations of males and femalese.g., picturing males as strong and intelligent or females as weak, emotional, and indecisive. While sex bias and stereotyping are related and frequently occur together, the focus of this study is on sex bias. There is evidence that sex bias exists in educational materials (e.g., Frasher & Walker, 1972; Grambs, 1972). Sex bias has also been observed on standardized achievement tests (Faggen-Steckler, McCarthy & Tittle, 1974; Tittle, 1974). These latter studies compared the frequency of male and female nouns and pronouns on eight major achievement test batteries. With one exception, each battery showed a higher frequency of male than female nouns and pronouns, with the ratios ranging from .86 (slightly more female references) to 14.00 (14 times more use of male nouns and pronouns). Similar biases have been found on other types of tests, such as interest inventories (Harmon, 1973). While there is emerging documentation of sex bias in educational materials and tests, there are few data on the effects of this bias on learning and test performance. Sex-bias effects may be present in the reportedly lower scores of girls on mathematics tests, for example (Maccoby & Jacklin, 1974); and there is speculation that such effects may be partly the result of bias in selecting test items (Donlon, cited in Tittle, 1974). Using items from classroom exams in an educational psychology course, Brown (1975) found some evidence of sex-of-test-taker-by-item interactions. For example, female students performed better on test items containing female sex references (e.g., she, Joan) than on items with male references (e.g., he, John) or no sex references. Related data from studies of race bias (Medley & Quirk, 1974; Schmeiser & Ferguson, 1978) are contradictory. The present study was designed to examine further the possible interaction between sex of subjects and sex referents (i.e., sex bias) in reading passages and test items.