Access to quality science, technology and innovation (STI) information by lawmakers, as one of the key determinants of the effectiveness of policies in sub-Saharan Africa, has generated much debate. The main objective of this article therefore is to examine the sources of, and access to, STI information available to lawmakers in Nigeria. We also investigate factors associated with the use of STI information from experts and other sources in the policymaking process in Nigeria. Data were collected from lawmakers in both the state and national assemblies across Nigeria. Those selected from the states are those with an active S&T structure, such as a fully fledged Ministry dedicated to S&T. The sample was drawn from legislators in S&T committees and other cognate ministries. Our findings reveal that most lawmakers do not use evidence-based STI information on a regular basis. We also note that the use of expert opinion is one of the main sources of STI information, while academic journals and public opinions are some of the least utilized sources. Some of the major factors that affect the use of information from experts are the law makers' level of education, number of years spent in the committee and duration of period as members of a committee. We recommend regular capacity-building programmes for legislators and their scientific advisers and personal assistants. This article is published as part of a collection on scientific advice to governments.