The development of a predictive model towards site‐selective deprotometalation reactions using TMPZnCl⋅LiCl is reported (TMP=2,2,6,6‐tetramethylpiperidinyl). The pKa values of functionalized N‐, S‐, and O‐heterocycles, arenes, alkenes, or alkanes were calculated and compared to the experimental deprotonation sites. Large overlap (>80 %) between the calculated and empirical deprotonation sites was observed, showing that thermodynamic factors strongly govern the metalation regioselectivity. In the case of olefins, calculated frozen state energies of the deprotonated substrates allowed a more accurate prediction. Additionally, various new N‐heterocycles were analyzed and the metalation regioselectivities rationalized using the predictive model. Metalation site prediction: The use of simple pKa calculations allowed a reliable prediction of metalation sites in various heterocycles, arenes, olefins, and alkanes, employing the mild base TMPZnCl⋅LiCl. Using this predictive model, also unexplored N‐heterocycles were investigated, and the obtained deprotonation sites rationalized readily.