The crystal structure of Rb2V3P4O17 has been determined from single‐crystal X‐ray diffraction data. Rb2V3P4O17 crystallizes in the orthorhombic space group Pnma (No. 62) with a = 17.502(7), b = 7.292(2), c = 11.399(6) Å3, V = 1455(1) Å3, Z=4, R=0.0295, RW = 0.0320 for 1129 unique reflections with I > 2.5 σ(I). The structure contains intersecting tunnels where the Rb+ cations are located. The framework can be described as consisting of V2O10 units formed from one VO5 square pyramid and one VO6 octahedron sharing a corner, and infinite chains of corner‐shared VO6 octahedra, which are linked in three dimensions by pyrophosphate groups. The structural formula is Rb2(VO)3(P2O7)2. A single‐phase product can be obtained by heating appropriate amounts of Rb4V2O7, VO2, V, and P2O5 in an evacuated fused silica tube at 950°C. Powder magnetic susceptibility data confirm the presence of V4+ (d1) ions without magnetic ordering down to 3 K.