Abstract There is currently no secularity scale with strong psychometric properties that would allow for the examination of the secularization process experienced by Muslims. Thus, the purpose of this article is to develop a psychometrically sound and quick-to-apply scale that can be used to measure the degree of secularity among Muslims. For exploratory factor analysis (EFA), an inventory with 65 items was applied to 1,573 university students, and it yielded a two-factor structure with an internal reliability of 0.975 for Daily Life factor and 0.952 for Faith and Prayer factor. After EFA, the confirmatory factor analysis (CFA) was performed with 4,391 individuals, and a structure that can be deemed very solid was found. The measurement invariance was also examined, and it was discovered that the scale can be used for various populations. In addition, the scale has convergent validity, a high test-retest result, and discriminant validity. The 25-item Secularity Scale has a new theoretical approach – which is not only based on faith and prayer but also daily life activities – and sound psychometric properties. Examining how secularity manifests itself in Muslim societies might be useful in describing, predicting, and explaining how individuals act in a variety of contexts. The scale might also help to avoid the use of approach utilized in Christian-centred secularity debates in the case of Muslim-majority societies.