The nature of the anion-π interaction has been investigated by carrying out ab initio calculations of the complexes of coinage metal anions (Au(-), Ag(-), and Cu(-)) with different kinds of π-systems. The binding energies indicate that gold anion has the highest and copper anion has the lowest affinity for interactions with π-systems. Different aspects of the anion-π interaction in these systems have been investigated, including charge-transfer effects (using the Merz-Kollman method), "atoms-in-molecules" (AIM) topological parameters, and interaction energies (using energy decomposition analysis, EDA). Our results indicated that, for most M(-)···π interactions, the electrostatic term provides the dominant contribution, whereas polarization, charge transfer, and dispersion effects contribute less than 25 % of the interaction. We believe that the present results should lead to a greater understanding of the basis for anion-π interactions of coinage metal anions.