Terpenes in essential oils (EOs) have recently received significant attention due to their potential to improve brain and whole-body health. A deeper understanding of the terpene composition of edible EOs is important for fully exploring their possible applications. In our study, we employed a comprehensive study using four different methods to analyze EO samples, including GC–MS with solid phase microextraction (SPME), liquid injection (LI), derivatization to trimethylsilyl ethers (TMSE), and LC-MS. Our findings revealed that relying on a single analytical method may be insufficient for detecting all terpenes in EOs. Despite identifying a total of 156 terpenes in the samples, only 58 were detectable across all 4 methods. To obtain a more accurate terpene profile of EOs, we advocate for the combined use of LI-GC and TMSE-GC. The terpenes detected by these two methods are complementary, enabling the detection of all terpenes with high VIP in the samples.