The effects of pressure gradient on turbulent heat transfer to or from planar surfaces are examined. Only incompressible, equilibrium thermal boundary layers are investigated. The equilibrium condition is characterised by the Clauser parameter beta. Temperature profiles which are parametric in beta and the turbulent Prandtl number, Pr(t) have been calculated for the range -0.54 less-than-or-equal-to beta less-than-or-equal-to infinity; corresponding in one end to a favorable pressure gradient flow beyond which no equilibrium boundary layer is possible and in the other end to turbulent flow at incipient separation, respectively. It is found that an overlap exists between the temperature law of the wall region and the outer defect law region for all values of beta and Pr(t), except when beta --> infinity. The existence of this overlap region gives rise to an expression for the Stanton number which is shown to be a function of beta and Pr(t). At incipient separation, the skin friction coefficient goes to zero while the wall heat flux remains finite. However, the wall heat flux and the Stanton number in this limit cannot be determined because of the neglect of viscous effects in the present analysis. A modified Reynolds analogy that accounts for the effects of beta and Pr(t) is deduced and the classical Reynolds analogy is shown to be valid only in the limit of beta goes to zero, Pr(t) goes to 1 and the Reynolds number based on the displacement thickness approaches infinity.