Polycrystalline Sm4Ni11In20 was obtained by arc-melting of metal ingots. A subsequent high temperature treatment was used for single crystal growth. The Sm4Ni11In20 crystal structure (U4Ni11Ga20 type; C2/m, a = 22.5457(3) Å, b = 4.34929(5) Å, c = 16.5479(2) Å, β = 124.592(2)°, R1 = 0.0358, wR2 = 0.0934) was determined by single crystal synchrotron radiation X-ray diffraction from 2014 independent reflections with I > 2σ(I). Sm4Ni11In20 extends the R
4Ni11In20 (R = Y, Gd, Tb, Dy, Ho) series of phases. The R
4Ni11In20 and RNi3In6 (LaNi3In6 type; R = La, Ce, Pr, Nd, Eu) series have similar compositions. Their structures share similar fragments; in particular the rare earth atom coordination polyhedra are pentagonal prisms with additional atoms.