The Maternal Interactive Beliefs Questionnaire (Johnston and Wong, 2002) assesses maternal beliefs about children's language development. This study investigated the psychometric properties of a Persian translation of this questionnaire. The translation followed the protocol of the World Health Organization. Psychometric properties were evaluated using data from 301 Iranian mothers of children aged two to five years. The internal consistency and test-retest reliability of the total scores were calculated for comparative purposes, and an exploratory factor analysis was conducted to determine the underlying structure. A principal component analysis revealed two components (accounting for 14.46% and 7.57% of the variance, respectively). The first component represented supportive maternal beliefs. The second component represented directive maternal beliefs. Cronbach's alpha for components one, two and the total scores were acceptable (0.73, 0.71, and 0.73, respectively), and the test-retest reliability of the total score was high (intra-class correlation coefficient = 0.97). Consistent with previous research, the findings indicated that the translated survey is reliable to be used with Iranian mothers. The novel finding is that the survey has two underlying and theoretically plausible components; therefore, the use of a total scale score is cautioned. We recommend future testing of the two components.