The compounds Ce₅₃Fe₁₂S₉₀X₃ (X = Cl, Br, I), which represent the first examples of rare-earth transition-metal sulfide halides, were prepared using the reactive-flux method, through reaction of Ce₂S₃, FeS, or Fe and S in a CeX₃ flux at 1320 K. Their structures were determined by single-crystal X-ray diffraction. The compounds are isostructural, crystallizing in the trigonal space group R3m with Z = 1 [Ce₅₃Fe₁₂S₉₀Cl₃, a = 13.9094(9) Å, c = 21.604(2) Å, V = 3619.7(4) ų; Ce₅₃Fe₁₂S₉₀Br₃, a = 13.916(1) Å, c = 21.824(2) Å, V = 3660.0(5) ų; Ce ₅₃Fe₁₂S₉₀I₃, a = 13.863(3) Å, c = 21.944(6) Å, V = 3652(2) ų]. The structure adopted is a stuffed variant of the La₅₂Fe₁₂S₉₀ structure type. Fe₂S₉ dimers of face-sharing octahedra are linked by face- and vertex-sharing capped CeS₆ trigonal prisms, forming a three-dimensional framework containing cuboctahedral cavities of two sizes. The smaller cavities accommodate alternative sites for disordered cerium atoms. The larger cavities, which remain empty in the parent structure, are filled by halogen atoms in Ce₅₃Fe₁₂S₉₀X ₃. Alternatively, the structure can be described as a 9-fold superstructure of the Mn₅Si₃ structure type (P6 ₃/mcm), with a = √3a′ and c = 3c′. Temperature-dependent magnetic susceptibility measurements suggest that Ce ₅₃Fe₁₂S₉₀I₃ may order antiferromagnetically at low temperatures.