Bounds are obtained for the L p norm of the torsion function v Ω , i.e. the solution of −Δv = 1, v ∈ H 1 0 (Ω), in terms of the Lebesgue measure of Ω and the principal eigenvalue λ 1 (Ω) of the Dirichlet Laplacian acting in L 2 (Ω). We show that these bounds are sharp for 1 ≤ p ≤ 2.