<p>Despite improvements in access to necessary frontline health services by health extension programs in Ethiopia, maternal and child health are still public health problems. Having access to relevant health messages is advantageous for a mother to have positive health outcomes. This study aims to assess unmet health information needs and associated factors among lactating mothers in the selected districts of the Gedeo zone, southern Ethiopia. A community-based cross-sectional study was conducted in the Gedeo zone, southern Ethiopia. The study used a multistage sampling technique with data collected from 687 lactating mothers using a face-to-face interviewer-based questionnaire. Respondents’ unmet needs for maternity-related health information are assessed using the question that comprises the adequacy, clarity, and timely access of health messages during their lactating period. The variable was measured by Likert scale questions, and a mean total of the score was computed to dichotomize for binary logistic regression analysis. A multivariable logistic regression was used to identify significantly associated variables with the dependent variable. About 41% of respondents have unmet health information needs. Two-fifths of the study participants disagreed with the easy understandability of available maternity-related health information. Age of the mother, educational status, level of health service utilization, availability of communication media, and distance from health facilities were significant influences on unmet health information needs. A significant number of mothers have an unmet need for health information on maternal and child issues. This study suggests health extension workers, health professionals, and concerned stakeholders should strengthen the delivery of health messages to satisfy mothers’ health information needs.</p>