This article describes the development and psychometric properties of the Rapport Scales for Investigative Interviews and Interrogations, Interviewee Version (RS3i), a multidimensional self-report questionnaire intended to measure interviewees' experience of rapport in forensic and intelligence interviews. Two studies are described. In Study 1, 80 simulated investigative interviews were conducted regarding a supposed case of domestic terrorism. Afterward, the 80 interviewee participants rated the interviews on rapport-related questionnaire items. Confirmatory factor analysis (CFA) of these ratings was used to construct a 21-item measure, the RS3i, comprising 5 Rapport Scales (Attentiveness, Trust/Respect, Expertise, Cultural Similarity, and Connected Flow) and a sixth scale, Commitment to Communication, that assesses an interviewee's motivation to be cooperative. In Study 2, another 94 simulated investigative interviews were conducted, after which interviewee participants rated the interview using the RS3i. A CFA of the Study 2 data confirmed the factor structure identified in Study 1. Good internal reliability and construct validity were demonstrated for most RS3i scales. Furthermore, scores on several scales were found to be higher when interviewers used rapport-based tactics and to correlate with the amount of information disclosed by interviewees during questioning. The RS3i can be a useful, psychometrically sound tool for use in rapport research and the training of forensic and intelligence interviewers.