Olive (Olea europaea L.) is one of the most economically relevant tree crops in the Mediterranean basin. In this study, a comparative proteomic along with metabolomic-wide investigation was carried out on drupes of Greek olive cultivar 'Chondrolia Chalkidikis', collected across six developmental stages (S), namely seed development (S1, S2), mesocarp development (S3, S4, S5) and full maturation (S6). These stages were first characterized through the dynamics of fruit weight, dimensions and color parameters such as lightness, redness and yellowness. Combined gas chromatography–mass spectrometry and reversed–phase liquid chromatography quadrupole–time–of–flight mass spectrometry (RPLC–QToF–MS) procedures quantified 47 primary (e.g. allose, galactose, quinic acid, sorbitol, stearic acid) and 21 secondary (e.g. elenolic acid, oleacin, rutin, luteolin, hydroxytyrosol) metabolites in mesocarp samples during development. Protein analysis via nano–LC coupled to HDAM Orbitrap mass spectrometer, identified 3258 proteins from which the 350 were differentially accumulated between the final maturation stages (S5 and S6). Olive genome-based functional annotation showed that the largest proportion of identified proteins were involved in primary metabolism [i.e. lipoxygenases (LOX1/5)], energy [i.e. ferredoxin NADP+ reductase (FNR)], signal transduction [i.e. serine/threonine kinases (SAPK2, SRK2A, STK), transcription [i.e. elongation factor 2 (EEF2)] and protein destination [i.e. serine carboxypeptidase (SCPL)]. This investigation provides a reference framework for further nutritional and breeding studies, also allowing cross comparison among other olive cultivars.