The interaction of conjugated organic molecules with surfaces is of fundamental interest and also important in many applied areas. Surface science investigations have advanced understanding of organic/metal interfaces, but the second electrode in organic optoelectronic devices – typically the transparent conductive oxide In2O3 – remains largely unexplored. Our work aims at closing this gap by examining the model system phthalocyanines on indium oxide surfaces. Phthalocyanines adsorbed on the In2O3(111) surface were studied experimentally with low temperature STM and AFM, combined with DFT calculations. A key aspect is the comparable size of the molecules and the surface unit cell, which allows a (1×1) arrangement despite the differing symmetries. Various metal phthalocyanines (MPc: CuPc, CoPc, etc.) are investigated to reveal the influence of the metal ion in the selection of adsorption sites, 2D condensation, and the formation of the first layer. We identify a common, robust adsorption site for different MPc that forces the molecules to overlap in the (1×1) structure of the first layer, and a less common site, where a (1×1) packing without overlap is realized.