A study on the shear model uncertainty and structural reliability of ultra high-performance fibre reinforced concrete (UHPFRC) beams with stirrups is presented. Model factors for the shear models given in the JSCE, AFGC and ACI 544 standards are characterised by comparison to non-linear finite element analyses (NLFEA). In comparison to other shear basic parameters, a notable negative correlation between model factors and product of the shear reinforcement ratio and strength (ρwfywm) is observed and therefore, care should be taken with respect to this variable when deriving partial resistance factors for UHPFRC beams with stirrups. When combined with stochastic descriptions of the remaining parameters that describe these analytical models, reliability values for beams designed to the JSCE and AFGC specifications are found to fall 9%, and 22%, below the target values of these standards, while reliability values for the ACI 544 agree with the target value specified for this standard, implying that the partial resistance factor specified for the ACI 544 is appropriate and in harmony with its presently characterised model factor