All solid surfaces—from the simplest monocrystals to the most complex composite nanomaterials—possess some degree of heterogeneity but determining how surface structure affects electrode functional properties (e.g., catalytic activity, selectivity, stability etc.) can often be challenging using traditional “bulk” electrochemical techniques. Scanning electrochemical cell microscopy (SECCM) is a nanopipette-based scanning probe microscopy (SPM) technique that utilises a mobile droplet cell to measure and visualise electrochemical (electrocatalytic) activity with high spatiotemporal resolution. This presentation will spotlight the use of SECCM for probing the electrocatalytic activity of nanomaterials on a commensurate scale to surface structural heterogeneities (i.e., nm–μm scale). It will be demonstrated that this approach is widely applicable to: well-defined monocrystals (e.g., transition metal dichalcogenides: MoS2 and WS2); structurally and/or compositionally heterogeneous polycrystals (e.g., polycrystalline Pt, Pd, Cu, etc) and; composite nanoparticle-on-support “ensemble” electrodes [e.g., β-Co(OH)2 nanoplatelets supported on carbon]. In particular, it will be emphasised how nanoscale-resolved information from SECCM is readily related to electrocatalyst structure and properties, collected at a commensurate scale with complementary, co-located microscopy/spectroscopy techniques (e.g., SEM, TEM, EBSD, AFM etc.), to allow structure−activity relationships to be assigned directly and unambiguously.