<p>Topological phases have been widely studied in quantum pure states, where exact symmetries protect them. Such symmetry-protected topological phases have been observed in a range of systems, from solid-state materials to synthetic quantum platforms. Recent theory predicts that average symmetry-protected topological phases can also emerge in mixed quantum states that arise in realistic settings with decoherence or disorder, but experiments have not yet established them. Here we report observations of a disorder-induced many-body interacting average symmetry-protected topological phase in an atom array. We introduce structural disorder by applying random offsets to the tweezer positions that define the lattice, which generates fluctuating long-range dipolar interactions between confined atoms. Spatially resolved atom–atom correlation functions for different dimer configurations characterize the resulting induced topological phase. We detect ground-state degeneracy across disordered configurations and compare it directly with the ordered case. Finally, by probing the quench dynamics of a highly excited state, we observe slower decay of edge spin magnetization than in the bulk, consistent with topologically protected edge modes in the disordered lattice.</p>