The purpose of this descriptive quantitative research study was to investigate the relationship between instrumental experience and sight-singing proficiency. This research was conducted in two phases: a quantitative survey of known high-achieving sight-singers and a comparison of sight-singing proficiency among participants with diverse musical backgrounds. Results indicated that participants with more than one type of previous musical experience might achieve higher sight-singing scores than those with only one type of previous musical experience. Participants with both choral and instrumental experience achieved higher sight-singing scores than participants with only one type of experience. Notably, participants who had taken a music theory course scored higher than participants with any other type of musical background. We discuss implications for future research.