Like other developing countries, Ethiopia has adopted its land administration system (LAS) based on socio-economic, environmental, and administrative circumstances to allocate and use the land. However, the two ineffective lines of urban and rural land tenure guidelines and legal frameworks play a surprising strategic role in access to land and peri-urban land development. Comprehensive land policies are prospects for today's peri-urban areas to become tomorrow's huge cities. This paper aims to investigate the factors influencing peri-urban land development in Assosa Town and indicate the design of effective LAS. A mixed research approach was employed, and data was collected from both primary and secondary sources. The sample respondents were selected using purposive sampling techniques and descriptive and inferential statistical data analysis methods were employed. The findings revealed that bifurcated and ineffective legal and institutional frameworks, limited public-private participation, and technical constraints adversely affect peri-urban land development. The dichotomized land use development has neglected urban fringe areas and contributed to the prevailing negative peri-urban land developments. Development resulted with limited access to serviced land and deprived of land development permit. <i>Following this, peri-urban landholders became a crucial contributor to the development of peri-urban land in a negative manner.</i> Almost all sampled households developed their land contrary to the legal frameworks and standards. The estimated results of the binary logit model indicate that several factors influence peri-urban land development, including sex, monthly household income, access to official land and land information, land disputes, the alternative land development tool, and institutional integration. It is recommended to have an all-in-one land policy and administration strategy to promote sustainable development in the study area and beyond.