2-Alkylcyclobutanones (2-ACBs) are recognized as a marker of irradiation in lipid-containing food products. Here, a rapid method for the analysis of 2-dodecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB) in irradiated food products using direct solvent extraction (DSE) was developed, and the extraction efficiency was compared to that of the Soxhlet extraction method (EN 1785), which is the official method for this analysis. Briefly, 2-ACBs were extracted either by using a Soxhlet apparatus or by DSE with n-hexane. The lipid extract was purified by GPC followed by a silica gel cartridge column. Finally, 2-DCB and 2-TCB were measured using GC-MS/MS. The extraction efficiency of 2-ACBs by the DSE method was similar to that of the Soxhlet extraction method. The trueness of 2-DCB and 2-TCB spiked at 50 ng/g in lipid extracts of beef, pork, chicken, cheese and salmon with the proposed method were 76.6% to 91.6% and 81.3% to 109.0%, respectively. The limits of detection for 2-DCB and 2-TCB in lipid extracts were 15 and 20 ng/g, respectively.