Background: Religiosity and/or spirituality (R/S) of physicians have been reported to inform behavior regarding religiosity and spirituality in clinical practice (R/S-B). Our aim was to study this association. Methods: Building upon a large international data pool of physician values we performed network and systematic literature searches using Google Scholar, Web of Science, Embase, Medline, and PsycInfo. Measures for R/S and R/S-B were selected for comparability with existing research. We performed a two-stage IPDMA using R/S coefficients from sample-wise multiple regression analyses as summary measures. We controlled for age, gender, and medical specialty. An additional sub-analysis compared psychiatrists to non-psychiatrists. Results: We found 11 eligible surveys from 8 countries (n = 3159). We found a positive association between R/S and R/S-B with an overall R/S coefficient of 0.65 (0.48–0.83). All samples revealed a positive association between R/S and R/S-B. Only 2 out of the 11 samples differed from the overall confidence interval. Psychiatrists had a higher degree of R/S-B, but associations with R/S did not differ compared to non-psychiatrists. Conclusions: We confirmed a significant association between R/S and R/S-B in this study. Despite large cultural differences between samples, coefficients remained almost constant when controlling for confounders, indicating a cultural independent effect of R/S on R/S-B, which to our knowledge has not been documented before. Such interaction can constitute both facilitators and barriers for high quality health care and should be considered in all aspects of patient and relationship-centered medicine.