The aim of this work is to understand the influence of textural, chemical. and structural properties on the reactivity of activated carbons toward air. Multiscale organization of activated carbons Was Studied using high-resolution transmission electron microscopy (HRTEM) and their quantitative structural data, like individual fringe length, interlayer spacing, and proportion of nonstackcd layers, were extracted using a specific image analysis procedure. Intrinsic properties like the specific surface area S-BET, pore volume, micropore width, and elementary composition were also measured. The reactivity of the carbon samples in air was quantified from the measurement of oxidation and ignition temperatures determined by thermogravimetry analysis coupled with a differential scanning calorimetry. The characteristics of the graphitic structures and the properties of the activated carbon materials were found to be dependent on the activation mode and the nature of the material. The results suggest that oxygen present in the form of surface oxygenated groups, the mineral content, and the dimensions of the basic structural units influence the reactivity of activated carbons. Highly stable carbons were found to contain less oxygen to carbon ratio, lower mineral content, and larger and better stacked polyaromatic layers.