Aims:  In T cells, protein kinase C (PKC) θ plays a major role in T‐cell receptor (TCR)‐mediated activation of a novel nuclear factor (NF)‐κB pathway that involves phosphorylation of p65 at serine 536 (Pp65Ser536). Bcl‐10 acts along the same pathway downstream of PKC θ to activate NF‐κB. The aim was to investigate the relationship between the expression of PKC θ, Bcl‐10 and P‐p65Ser536 proteins and their prognostic significance in peripheral T‐cell lymphomas (PTCLs).Methods and results:  Paraffin‐embedded tissues from 30 patients with PTCLs treated with curative intention were evaluated retrospectively. Expression of PKC θ, Bcl‐10 and P‐p65Ser536 proteins was assessed using immunohistochemistry. Expression of PKC θ was detected in 22 of 30 cases (73%), Bcl‐10 in 20 of 30 (67%) and P‐p65Ser536 in 21 of 30 (70%). Bcl‐10+ tumours were associated with PKC θ (18 of 22) (P < 0.0001) and Pp65Ser536 (19 of 21) expression (P < 0.0001). Patients with Bcl‐10+ or P‐p65Ser536+ tumours fared better, with a 5‐year overall survival of 48 and 45%, respectively, versus 0% for negative tumours (P = 0.029 and P = 0.04, respectively).Conclusions:  Bcl‐10 is expressed in PTCLs, correlates with PKC θ and Pp65Ser536 expression and seems to be associated with better survival.