The present invention provides a novel multilayer structure having good gas barrier properties and good water vapor barrier properties and further having high retort resistance and a packaging material including the multilayer structure. The present invention relates to a multilayer structure including a base (X) and a layer (Y) stacked on the base (X). The layer (Y) contains an aluminum-containing compound (A) and an organic phosphorus compound (BO), and the organic phosphorus compound (BO) contains a phosphorus atom-containing functional group and at least one metal ion (Z) selected from ions of metals of Groups 1 to 12 of the periodic table, the content of the metal ion (Z) being 0.4 to 8.0 mol % relative to the content of the phosphorus atom-containing functional group.