The syenitic rocks of South Rallier du Baty Intrusive Complex (SRBIC) represent in- trusions into the oceanic plateau basalts of the south-western Kerguelen Islands. The SRBIC was previously interpreted as a typical ring complex due to magma emplace- ment with cauldron subsidence. Our new structural and geochronological data reveal that it is a laccolith built between 11.6 and 7.9 Ma by successive injections of magma sheets around the crust–mantle boundary, with an average injection rate between 0.8 and 1.4 × 10−4 km3/year. These results establish strong similarities between the SRBIC, the only recorded example of a felsic laccolith in an oceanic intraplate setting, and many continental plutons emplaced in various geodynamic setting. The SRBIC thus has the characteristics of a continental plutonic complex emplaced in an oceanic plateau crust. We postulate the critical parameter relevant to causing such similari- ties and plutonic magmatism is crustal thickness.