This study describes the feasibility of ATR-FTIR spectroscopy combined with multivariate data analysis for discrimination and estimation of the firing conditions of the shard samples excavated from the sanctuary of Hecate at Lagina. ATR-FTIR spectra of 53 shard samples were collected in the different spectral regions (1700−825, 825−400, 1700−400 cm−1) and the similarities and differences in the samples were assessed in 36 principal component analysis (PCA) models that use normal, first, and second-derivative spectra of the spectral regions. The performance of PCA models developed was evaluated by principal component (PC) percentages, eigen-values, the factor numbers reached, and the number of samples outside of explained variance (95%). It was observed that the PCA model employing normal spectra (825−400 cm-1) with 31 smoothing points has the best statistical results for discriminating against the shards of the sanctuary of Hecate based on their different mineralogical composition. The second-derivative ATR-FTIR spectra (two polynomial degrees and 11 smoothing points of Savitzky-Golay method) in the range of 1700−400 cm-1 was successfully used to determine the mineralogical composition and the firing conditions of the shard samples of the sanctuary of Hecate. The results showed that all shard groups have the characteristics of mica-type (micaceous) clay, mainly contain muscovite, quartz, gypsum, and meta-smectite, but also a remarkable amount of firing mineral such as diopside. The occurrence of appreciable amounts of muscovite, diopside, and hematite suggested that most of the shards have been fired at temperatures about 800 °C, but lower than 950 °C, in the oxidizing atmospheric conditions.