Research on sexual harassment has shown that although half of all women experience unwanted sex-related behaviors in work and school, only 4% to 20% label those experiences as sexual harassment (Magley, Hulin, Fitzgerald, & DeNardo, 1999; Stockdale, Vaux, & Cashin, 1995). Moreover, while research and literature on face-to-face sexual harassment continues to grow, little research has examined sexual harassment in an Internet context. Because of this, much of what is known about Internet-based sexual harassment comes from research conducted on face-to-face sexual harassment. The current study establishes a foundation of understanding and develops a measure of experiences of sexual harassment on the Internet (i.e., cyber-sexual harassment). Cyber-sexual harassers use the Internet as a way to connect with acquaintances from off-line social interactions (i.e., work and school), or complete strangers, to perpetrate their victims through gender harassment, the exhibition of unwanted sexual attention, and/or the use of sexual coercion. In a British survey, 41% of female regular Internet users reported being sent unsolicited pornographic materials, harassed, or stalked on the Internet (Griffiths, 2000). Such a large number of women encountering offensive sex-related experiences on the Internet prompts further understanding of these experiences and others like them. The purpose of the current study is to add to the developing body of literature on cyber-sexual harassment by creating a measure of cyber-sexual harassment. Twenty-four female undergraduate students participated in focus groups of two to six people. Guided by predetermined questions, these groups discussed their positive and negative experiences on the Internet. Information gathered was used to create the Cyber-Sexual Experiences Questionnaire, modeled after the Sexual Experiences Questionnaire (Fitzgerald, Gelfand, & Drasgow, 1995). The 21-item measure consists of questions related to the participant’s cyber-sexual harassment experiences and whether the participant labels her experiences as cyber-sexual harassment. Responses for the frequency of each item range between one (never) to five (most of the time).