Benchmarking simulation codes for electron transport and scattering in matter is a crucial step for estimating uncertainties in many applications. However, experimental data for electron energies of a few MeV are too scarce to make such comparisons. We report here the measurement and the quantitative analysis of backscattering probabilities of electrons in the energy range 0.1 to 3.4 MeV impinging on a Ce-doped YAlO3 (YAP:Ce) scintillator. The setup consists of a 2×2⁢𝜋 calorimeter which enables, in particular, the inclusion of large incidence angles. The results are used to benchmark various scattering models incorporated in Geant4, showing relative deviations smaller than 5% between experiment and simulations. They demonstrate the current rather high reliability of the simulations when employing appropriate electromagnetic physics lists.