Display omitted •Distinct differences in the ATR-FTIR spectra of anhydrous milk fat and Vanaspati ghee (hydrogenated vegetable oil) were observed.•PCA in the ranges of 1120–1080 cm−1 and 985–955 cm−1 showed distinct clusters of all samples.•SIMCA approach showed 100% classification efficiency for control and adulterated samples.•ATR-FTIR coupled with chemometrics could detect even 1% of vegetable ghee in milk fat. Anhydrous milk fat, a household staple in domestic India, faces the threat of adulteration due to its high cost. Vanaspati ghee (hydrogenated vegetable oil) is one such adulterant that has been reported in ghee. The presence of vanaspati ghee (hydrogenated vegetable oil) in anhydrous milk fat was investigated using ATR-FTIR spectroscopy in combination with chemometric techniques. Spectral data were collected for pure ghee, vanaspati ghee, and ghee samples spiked with vanaspati ghee at different levels (1 %, 3 %, 5 %, 7 %, 9 %, 12 %, and 15 %), encompassing the wavenumber range of 4000–500 cm−1. PCA analysis revealed distinct clustering patterns in specific wavenumber regions (1120–1080 cm−1 and 985–955 cm−1) at a significance level of 5 %, effectively distinguishing pure ghee from adulterated samples. SIMCA showed 100 % classification efficiency for pure and vanaspati ghee samples. Additionally, the developed PLS and PCR models exhibited high R2 values (∼1), indicating robust predictive accuracy for detecting vanaspati ghee adulteration in ghee at different concentrations. Thus, ATR-FTIR and chemometrics successfully enabled the detection of vanaspati ghee in milk fat, with a sensitivity as high as 1 %.