There is a gender gap in Internet use: Two thirds of users are males, and males account for 77% of on-line time. This article reviews related research to explain these differences. From childhood on, males are more experienced with computers and have more favorable attitudes toward computers than do females. These gender differences in computer experiences and attitudes as well as the masculinization of the computer culture may be transferred to Internet use and attitudes. In fact, the Internet culture was developed by its earliest users, primarily male scientists, mathematicians, and technologically sophisticated computer hackers. This culture can be discomforting and alien to females. For example, netiquette norms tolerate uncensored hostility and even harassment, which women may find offensive. Gendered linguistic differences also affect Internet discussion groups. Linguistic analysis of on-line academic discussion groups found males' postings were status enhancing and adversarial whereas females' postings were supportive and tentative. Further, when females began to approach domination on male-dominated lists, they were ignored, trivialized, or criticized by males. Finally, evidence of greater pathological Internet use by males and a technological mystique surrounding the Internet are presented. Anticipated changes regarding gender differences in Internet use and future directions for research are discussed.