Three pyridine-based Schiff bases namely N²,N⁶-bis(4-methylbenzylidene)pyridine-2,6-diamine (DAP-1), N²,N⁶-dibenzylidenepyridine-2,6-diamine (DAP-2) and N²,N⁶-bis(4-nitrobenzylidene)pyridine-2,6-diamine (DAP-3) were synthesized, characterized, and their corrosion inhibition performance was studied on mild steel (MS) in 1 M hydrochloric acid solution using electrochemical experiments and theoretical study.The results showed that all the three DAPs act as mixed type corrosion inhibitors, and are adsorbed on MS surface by following Langmuir adsorption isotherm. The methyl-substitutedDAP-1 showed maximum inhibition effiency of 98.5% at 40 mgL^-1. The formation of inhibitor film on MS surface was confirmed by SEM andAFM. Quantum chemical calculations and Monte Carlo simulations were used to understand metal-inhibitor interaction and orientation of adsorption ofDAP molecules.Agood correlationwas observed between theoretical and experimental results.