Slums and informal housing developments in Akure are growing at an unprecedented rate. It is on this basis that this work sets out to map out the indices of slum and informal housing development in Akure, Ondo State, Nigeria. High-resolution satellite data, as well as primary and secondary data, were used in the study. Based on collected data, ArcGIS 10.3.1 software was used to prepare a base map showing the existing land use, built up area in 1986, 2002, and 2019, and indices of slums, or informal housing in Akure. The indices were rated on a scale of 1–5 and the results obtained revealed that socio-economic indices [housing shortage, lack of affordable housing, high incidences of urban poverty, high incidences of rural or urban–urban migration and unemployment], institutional indices [poor enforcement of planning laws, unclear regulation and long procedures for building plan approvals, and lack of planning/development plans], political indices [inadequate provision of sites and services, tenure insecurity and eviction, and poor resettlement programme by the government] and environmental indices [high density of development and overcrowding, inadequate neighbourhood facilities and services, and inadequate sanitation] are most significant in the core and peripheral areas of Akure. The study recommends slum upgrading programmes oriented to the betterment of the current conditions of slum households and neighbourhoods and formal housing aimed at securing access to adequate housing for all, in particular the most vulnerable, promoting affordable and safe solutions and inclusive housing finance systems.