<p>Understanding the electric double layer (EDL) of stepped Pt electrodes is crucial for comprehending the reaction environment for electrocatalytically relevant Pt electrodes, which typically comprise a complex mixture of facet orientations, steps and defects. Here we systematically investigate the EDL structure of these surfaces by periodically perturbing (111) terraces by either (110)- or (100)-type steps. We find that the minimum in the differential capacitance <i>C</i>_d,min in 0.1 mM HClO₄ is highly structure sensitive. We attribute this observation to inherent differences in affinity for H₂O dissociation between (110) and (100) facets. Using a continuum model, we confirm that the potential of <i>C</i>_d,min (<i>E</i>_d,min) closely approximates the potential of zero free charge <i>E</i>_pzfc for the (110)-stepped series. Together with ab initio molecular dynamics simulations, we reveal that OH_ads at step sites leads to a different step-density-dependent trend between <i>E</i>_pzfc and the work function. Our approach yields a unified picture of the EDL structure on stepped Pt surfaces, bridging the gap between model single-crystal surfaces and practically relevant heterogeneous Pt electrodes.</p><p></p>