There is a long history of operationalizing theoretical constructs of language proficiency by developing language proficiency scales. However, existing scales are not directly applicable in teaching and assessing Chinese as a second language (CSL) reading in US higher education contexts. Teachers need guidance regarding what component reading skills/knowledge should be taught and measured. This study developed a CSL Reading Proficiency Scale aligning to Koda’s (2005) theoretical framework that models L2 reading as a three-factor construct. The scale development began with modeling the construct of CSL reading ability on the basis of literature review. Drawing on this process, an operational descriptive scheme and a descriptor pool were established and subjected to expert review of content validity. Descriptors that survived expert review were then compiled into a Likert-scale questionnaire. This instrument was tested through teachers’ evaluations (N = 179) of whether CSL learners ‘can do’ what were denoted by descriptors. Confirmatory factor analysis exhibits solid goodness of fit between descriptors and the hypothesized three-factor model. The total score and the three subscale scores show high reliability. Evidence of convergent validity, discriminant validity, and concurrent validity indicates that the Scale measures CSL reading ability as intended.