A flow structure based triple-product correlation model developed by Nagano and Tagawa [J. Fluid Mech. 215, 639 (1990)] has been expanded to three-dimensional turbulent flows. Three-dimensional turbulent boundary layer data obtained away from the vortex in a wing-body junction flow are analyzed to calculate the contributions from eight velocity octants to the stresses and higher-order products. The analysis showed that the sweep and ejection modes dominate the flow physics of some shear stresses and some triple products, while the interaction modes are negligible away from the wall. These experimental observations are used together with the extended Nagano-Tagawa mathematical model to obtain relations among the triple products in three-dimensional turbulent boundary layers that can simplify the turbulent diffusion modeling used in Reynolds-averaged Navier-Stokes equations. Results show that (u) over cap (3), (u) over cap (2)(v) over cap, and (v) over cap (3) triple product correlations can be modeled if an appropriate turbulence model is described for the (u) over cap(v) over cap (2) triple product correlation, and that (u) over cap (2)(w) over cap(v) over cap (2)(w) over cap triple products correlations can be modeled if an appropriate turbulence model is described for the uvw triple product correlation.