The purpose of this study was to determine if an instrument could be developed to measure spiritual engagement. The study resulted in the Spiritual Engagement Instrument (SpEI) concept comprised of four factors that included the following: worship that explained 57.8% of the variance and Cronbach’s alpha of .94, meditation that explained 12.7% of the variance and Cronbach’s alpha of .96, fasting that explained 9.58% of the variance and Cronbach’s Alpha of .98, and rest that explained 5.16% of the variance and Cronbach’s alpha of .99. The four factors together explain 85.24% of the variance. The four spiritual engagement scales within the Spiritual Engagement Instrument (SpEI) show significant correlation with other similar but different measures of spirituality, the Brief Multidimensional Measure of Religiousness/Spirituality scale and Daily Spiritual Experience Scale, confirming convergent validity. A supplemental validation study was performed using CFA (χ2 = 238.48 (df = 158), p < .001, CFI = .98, TLI = .97, RMSEA = .06). This SpEI offers researchers a tool that might be used as a pre-/post-test measure in conjunction with a spiritual development program or to measure effects of the four factors of spiritual engagement with other social constructs such as job satisfaction, normative commitment, or leadership behaviors. Ethical behavior may be influenced by individual worldview and underlying religious practices, so the SpEI offers a validated instrument to study the cycle of behaviors, attitudes, and beliefs of spiritual practices that may influence ethics.