The invention is based on the discovery that certain crosslinkable functional groups can be incorporated into olefin oligomers, thereby making these functionalized olefin oligomers useful as thermosetting resin compositions. In particular, there are provided olefin oligomers containing pendant maleimide groups. These materials are readily prepared via cationic co-polymerization of cationically polymerizable olefin monomers and maleimide monomers containing a cationically polymerizable functional group.