We demonstrate electrical control of the A-exciton interband transition in mono- and few-layer MoS2 crystals embedded into photocapacitor devices via the DC Stark effect. Electric field-dependent low-temperature photoluminescence spectroscopy reveals a significant tuneability of the A-exciton transition energy up to ∼16 meV from which we extract the mean DC exciton polarizability ⟨β̅N⟩ = (0.58 ± 0.25) × 10–8 Dm V–1. The exciton polarizability is shown to be layer-independent, indicating a strong localization of both electron and hole wave functions in each individual layer.