DDI may stand for:
Companies and organizations DD International, international TV channel in India Development Dimensions International, a talent management company Direct Democracy Ireland, a political party in Ireland KDDI, formerly DDI, a Japanese telecommunications company Data Disc, Incorporated, a defunct American computer hardware company Data Design Interactive, a defunct shovelware gaming company
Science Drug–drug interaction Didanosine, an antiretroviral drug
Technology Acronym for DNS/DHCP/IPAM; see IP Address Management Direct dial-in, or direct inward dialing, a telecommunications service DirectX Device Driver Interface D&D Insider, an online method used to deliver Dungeons & Dragons content Diverging diamond interchange, a road structure that guides traffic
Other uses Dance Dance Immolation, interactive performance piece Data Documentation Initiative, a standard for describing surveys, questionnaires, and statistical data files Democracy-Dictatorship Index, a binary measure of democracy and dictatorship Divisional detective inspector, a rank in the Criminal Investigation Department of London's police