Inquiry engagement is a newly defined construct that represents the participation in carrying out practices of science and engineering to achieve learning outcomes and is influenced by learners' personalities and teachers' roles. Expectancy value theory posits that attainment values are important components of task values that, in turn, directly influence students' achievement-related choices and performance. The current paper developed and validated the McGill Attainment Value for Inquiry Engagement Survey (MAVIES) with undergraduate students in STEM disciplines. The MAVIES is a 67-item, learner-focused survey that addresses four components that are theoretically important for engaging in scientific inquiry: (a) teachers' roles, (b) students' personalities, (c) inquiry learning outcomes, and (d) practices of science and engineering. Evidence for internal consistency and construct, content, and criterion validity was obtained from 85 undergraduates who had experience with scientific inquiry in diverse STEM fields. Confirmatory factor analyses confirmed factors that were consistent with role theory, Big Five personality traits, revised Bloom's learning outcomes, and the Next Generation Science Standards. The MAVIES instrument is a reliable and valid instrument for measuring undergraduate students' attainment values for scientific inquiry engagement in STEM disciplines.