The overlap between religion and spirituality made it difficult to develop a refined comprehensive measure of interfaith spirituality (IFS). The current study tries to fill this gap. The authors, based on extensive review of different spiritual religious traditions, developed a conceptual framework of IFS that includes 5 interconnected components: direct connection with the creating force, asceticism, the unity of existence, meditation, and divine love. Using experts and focus groups, they developed the measure of IFS that included items that represented the 5 components. The measure (25 items), and its short form (four items) were tested on a sample of 490 in Egypt (Christians, N ϭ 247 and Muslims, N ϭ 243), 58.6% women, and included 3 subregional groups (Qena, upper Egypt, N ϭ 210; Fayoum, middle Egypt, N ϭ 184; and Cairo, N ϭ 96). Ages ranged from 14 to75, with M ϭ 26.03, SD ϭ 10.90, with 20.4% adolescents. Because unity of existence factor has been significantly loaded on only two items in the exploratory factor analysis, this factor was dropped. Confirmatory factor analysis validated 4 factors and found a second-order unitary construct of IFS. The model of IFS was strictly invariant across religion, gender, age, and region groups. IFS, its subscales, and its short form were found to have good interitems and test-retest reliability, criterion, convergent, divergent, predictive and incremental validity. They were moderately associated with religiosity, higher self-esteem, higher emotional regulation, higher will-to exist-live and survive, and posttraumatic growth. They were negatively associated with posttraumatic stress disorder (PTSD), depression, externalizing, thought disorder, and psychopathology in general. Future studies need to refine the measure and replicate the results.