DII may refer to:Days in inventory, an accounting term Dii, the Thracian tribe Dii language DiI, a hydrophobic cyanine dye used in cell biology Dietary Inflammatory Index Delegation of the Ismaili Imamat, the Delegation of the Ismaili Imamat Diablo II, a sequel to the computer game Diablo Defence Information Infrastructure, the UK's secure military communications network Dynamic Invocation Interface, part of the CORBA standard 502, DII in Roman numerals