AbstractGiven a distribution of pebbles on the vertices of a connected graphG, apebbling moveonGconsists of taking two pebbles off one vertex and placing one on an adjacent vertex. Theoptimal pebbling numberofG, denoted byπopt(G), is the smallest numbermsuch that for some distribution ofmpebbles onG, one pebble can be moved to any vertex ofGby a sequence of pebbling moves. LetPkbe the path onkvertices. Snevily defined then–kspindle graph as follows: takencopies ofPkand two extra verticesxandy, and then join the left endpoint (respectively, the right endpoint) of eachPktox(respectively,y), the resulting graph is denoted byS(n,k), and called then–kspindle graph. In this paper, we determine the optimal pebbling number for spindle graphs.