The Early Childhood Oral Health Impact Scale (ECOHIS) has been developed in English for determining oral health-related quality of life (OHRQoL) in the preschool children. It has been translated and validated in different languages to suit different cultures. The ECOHIS is, till date, the only tool available for research in this field on preschool age children. A similar version of this tool is not available for use in the local language Malayalam. This study aimed to develop and validate a Malayalam version of the ECOHIS (M-ECOHIS). The study was conducted with a cross-sectional design. The ECOHIS was translated into Malayalam by forward-backward translation and tested for face and content validity. The parents of 300 children were administered the M-ECOHIS and an additional global oral health (GOH) question. The children were examined for the presence of early childhood caries (ECC) which was recorded using the defs index. The internal consistency reliability, test-retest reliability, interobserver reliability, and convergent and discriminant validity were assessed. The tool possessed good internal consistency (Cronbach's alpha = 0.879; item total correlation 0.2832-0.7617); the test-retest reliability and interobserver reliability assessed using ICC (ICC = 0.9457 and 0.9460, respectively) was acceptable. The Spearman's correlation coefficient of the ECOHIS and the GOH scores, r = 0.725; P = 0.01 supported the convergent validity. The mean ECOHIS scores of children having ECC with mean ECOHIS scores of children without ECC were compared using unpaired t-test and found to be statistically significant supporting the discriminant validity of the scale. The M-ECOHIS can be used to assess the OHRQoL of preschool children in the Malayalam speaking community.