<p>Rapid urbanisation and evolving consumption patterns in semi-urban Nigeria have intensified household solid waste generation, posing serious environmental and public health concerns. This study examined the drivers, characteristics, and management of household solid waste in Iwo, Nigeria, and their implications for sustainable environmental quality. A positivist research philosophy and quantitative research design were adopted to enable objective analysis of waste-related behaviours. Using a multistage sampling technique, 636 households were selected across residential neighbourhoods in Iwo. Primary data were collected through structured questionnaires and analysed using descriptive statistics and factor analysis. Findings revealed that organic and food waste constituted the dominant waste stream, with households generating an average of 1.5 rice sacks weekly, while plastics, paper, and packaging materials were comparatively lower. Factor analysis identified four major determinants of waste generation and management, explaining 69.9% of the total variance: household consumption patterns, social events and festivities, seasonal variations, and sources of household consumables. Waste management practices were largely informal, relying on community dumping sites, itinerant waste collectors, and limited municipal services. Economic benefits from recyclable materials motivated nearly half of respondents to sort waste, whereas environmental awareness and regulatory compliance had minimal influence. Infrastructural deficiencies, blocked drainage systems, and unplanned urban expansion further heightened flooding and vector-borne disease risks. The study recommends strengthening formal waste management systems, integrating informal actors, promoting household recycling and composting, and improving drainage infrastructure to enhance environmental sustainability in Iwo.</p>