Highly efficient blue electrophosphorescent organic light‐emitting diodes incorporating a bipolar host, 2,7‐bis(diphenylphosphoryl)‐9‐4‐(N,N‐diphenylamino)phenyl‐9‐phenylfluorene (POAPF), doped with a conventional blue triplet emitter, iridium(III) bis(4,6‐difluoro‐phenyl)pyridinato‐N,C2´picolinate (FIrpic) are fabricated. The molecular architecture of POAPF features an electron‐donating (p‐type) triphenylamine group and an electron‐accepting (n‐type) 2,7‐bis(diphenyl‐phosphoryl)fluorene segment linked through the sp3‐hybridized C9 position of the fluorene unit. The lack of conjugation between these p‐ and n‐type groups endows POAPF with a triplet energy gap (ET) of 2.75 eV, which is sufficiently high to confine the triplet excitons on the blue‐emitting guest. In addition, the built‐in bipolar functionality facilitates both electron and hole injection. As a result, a POAPF‐based device doped with 7 wt% FIrpic exhibits a very low turn‐on voltage (2.5 V) and high electroluminescence efficiencies (20.6% and 36.7 lm W−1). Even at the practical brightnesses of 100 and 1000 cd m−2, the efficiencies remain high (20.2%/33.8 lm W−1 and 18.8%/24.3 lm W−1, respectively), making POAPF a promising material for use in low‐power‐consumption devices for next‐generation flat‐panel displays and light sources. Devices incorporating the novel host POAPF, which possesses a high value of ET, satisfactory thermal stability, and bipolar characteristics, display highly efficient blue electrophosphorescence. The 7 wt% FIrpic‐doped device exhibits a very low turn‐on voltage (2.5 V) and high electroluminescence efficiencies (20.6% and 36.7 lm W−1).