Congressional lobbying by education-related interest groups is an understudied subject in education research. This research brief uses Congressional lobbying expenditure data from 1998 to 2017 to examine trends in lobbying behavior by labor unions, K-12 education providers, and public, private non-profit, and for-profit higher education institutions. Education interest groups have spent in excess of $2 billion lobbying Congress since 1998. Higher education institutions represent a disproportionate share of lobbying activity and expenditures, accounting for almost 70 percent of education-focused interest groups and around 80 percent of education-related lobbying expenditures. Lobbying expenditures steadily rose until 2011 before rapidly declining. The brief speculates as to the possible reasons for these trends and concludes with a call for greater research on lobbying for education.