  We prove a duality relation for generalized basic hypergeometric functions.
It forms a $q$-extension of a recent result of the second and the third named
authors and generalizes both a $q$-hypergeometric identity due to the third
named author (jointly with Feng and Yang) and a recent identity for the Heine's
${}_2\phi_{1}$ function due to Suzuki. We further explore various consequences
of our identity leading to several presumably new multi-term relations for both
terminating and non-terminating generalized basic hypergeometric series.
Moreover, we give confluent versions of our results and furnish a number of
explicit examples.
