With age and the onset of the elderly, people are more prone to mental disorders including feeling of loneliness, anxiety, and depression, due to numerous losses such as loss of spouse, relatives, friends, occupation, social and economic status, beliefs, etc., as well as due to the reduction of physiological functions and mobility. Accordingly, this study aims to compare the effectiveness of metacognitive therapy and spiritual therapy on cognitive dissonance and feeling loneliness in the elderly living in nursing homes. This was a quasi-experimental study with pretest-posttest follow-up (PPF) and control group design. The statistical population consisted of all the elderly, aged from 60 to 75 years living in nursing homes of Tehran, Iran, among which Kahrizak nursing home was selected using convenience sampling method. In this way, 30 aged people (three groups of 10) with an average age of 60-75 years were selected using convenience sampling along with inclusion and exclusion criteria, and were randomly assigned into two experimental and one control groups. Participants were exposed to eight 90-minute sessions (2 sessions a week) of Wells’,metacognitive therapy and Boalhari’, s spirituality therapy. The follow-up step was conducted one month after the posttest step. Utilized to collect data were Harmon-Jones dissonance arousal reducing questioner and Dehshiri et al. ’, s loneliness questionnaires. Data were analyzed using univariate analysis of covariance (ANCOVA) and Bonferroni post-hoc test in SPSS-22. The results demonstrated that both metacognitive therapy and spiritual therapy groups had a significant difference with control group in terms of the components of cognitive dissonance and feeling of loneliness in posttest and follow-up steps (P<0. 05). However, there was no significant difference between two groups of metacognitive therapy and spiritual therapy in terms of the components of cognitive dissonance and loneliness (P>0. 05). Given the findings of this study, metacognitive therapy and spiritual therapy can be effective in reducing cognitive dissonance and loneliness in the elderly.