Early after infection, large quantities of HIV are trapped on follicular dendritic cells (FDCs) thus establishing a potent reservoir of infectious virus adjacent to highly susceptible CD4-bearing T lymphocytes. Throughout much of the disease course, active HIV infection is largely confined to sites surrounding FDCs suggesting that this microenvironment is highly conducive to infection. FDCs maintain HIV infectivity and trapped virus can cause infection even in the presence of neutralizing antibody. FDCs also contribute signaling to the germinal center microenvironment that appears to increase HIV infection and replication. This article discusses these FDC contributions to HIV pathogenesis.