Improper solid waste management in urban and semi-urban cities of developing countries is the source of environmental pollution and public health concern. This study aimed to assess the households’ knowledge, attitudes and practices of solid waste management and associated factors in Gelemso town. A community-based cross-sectional study design was used to assess the households’ KAP of SWM in Gelemso town. A systematic random sampling technique was used to recruit 390 households from Gelemso town and data was collected using a structured questionnaire. Data analysis was carried out using SPSS version 22.0 software. Bivariate and multivariate analyses were used to predict the improper SWM practices. From 390 households included in the study, 61.3% of them were females. Generally, most households had correct knowledge and positive attitudes towards SWM but poor practice was observed in the study area. About 96% of the households considered solid waste as a source of environmental pollution and close to 92% of them replied that solid waste can be used for compost preparation. Majority (87.4%) of the households “strongly agreed” about the potential risk associated with improper solid waste disposal and nearly 80% of them also “strongly agreed” that proper SWM is crucial to create a healthy environment in the community. Nearly 80% had practiced improper SWM. Logistic regression analyses indicated that lack of experience in sorting solid waste, ways of removal, knowledge about reduce, reuse and recycle, absence of adequate solid waste landfills, and lack of door-to-door waste collections services were identified as the major contributing factors for the improper SWM practice in Gelemso town. In conclusion, the majority of the households had practiced improper SWM, such as disposing of solid waste in the backyard, along the roadsides, in gully and burned. These malpractices can significantly affect the environment and public health of the residents.