The present study set out to determine the role of religiosity/spirituality and mindfulness skills of parents in family functioning. This descriptive-correlational research was web-based and its statistical population was comprised of all parents of elementary school students in Maku city during the 2020-2021 academic year. Based on Cochran's formula, 384 parents (192 fathers and 192 mothers) were selected as samples through convenience sampling. Data were collected using the Religiosity/Spirituality Questionnaire (Haber et al., 2007), Mindfulness Skills Questionnaire (Baer et al., 2004), and the McMaster Family Assessment Device (Epstein et al., 1983). The data were analyzed using Pearson correlation and multiple regression methods with SPSS software version 24. The results showed a significant positive relationship between religiosity/spirituality and mindfulness skills with better family functioning (p<0.05). Religiosity/spirituality and its dimensions could account for 53% of the variance in family functioning, while mindfulness skills and their dimensions were able to explain 61% of the variations (p<0.001). Based on these results, planning to enhance family functioning through improving religiosity/spirituality and mindfulness skills is essential, and educational workshops can be utilized for this purpose.