Let P = P (h) be a semiclassical pseudodifferential operator on a Riemannian manifold M . Suppose that u(h) is a localised, L 2 normalised family of functions such that P (h)u(h) is O(h) in L 2 , as h → 0. Then, for any submanifold Y ⊂ M , we obtain estimates on the L p norm of u(h) restricted to Y , with exponents that are sharp for h → 0. These results generalise those of Burq, Gérard and Tzvetkov [4] on L p norms for restriction of Laplacian eigenfunctions. As part of the technical development we prove some extensions of the abstract Strichartz estimates of Keel and Tao [7].Let P = P (h) be a semiclassical pseudodifferential operator on a Riemannian manifold M . We will assume that P has a real principal symbol, and that its full symbol is smooth in the semiclassical parameter h. Other more technical assumptions on P are given in Definition 1.6. We prove estimates for approximate solutions u = u(h) to the equation P (h)u(h) = 0. As usual in semiclassical analysis we assume that u(h) is defined at least for a sequence h n tending to zero.Our precise definition of approximate solution, or quasimode, is thatThis definition is natural with respect to localisation: if, and χ is a pseudodifferential operator of order zero (with a symbol smooth in h), then P (χu) is also O L 2 (h). We will make the assumption that u(h) can be localised, see Definition 1.3, and therefore will be able to reduce the problem to one of local analysis.Given a submanifold Y of M , we estimate the L p norm of the restriction of u to Y , assuming the normalisation condition u L 2 (M ) = 1. These estimates are of the form u L p (Y ) ≤ Ch −δ where δ depends on the dimension n of M , the dimension k of Y and p (except for one case where there is a logarithmic divergence) -see Theorem 1.7. In every case the exponent δ(n, k, p) given by Theorem 1.7 is optimal. Figure 1 shows the exponent δ for a hypersurface and, for comparison, the L p estimates over the whole manifold (Sogge [11] for spectral clusters and Koch-Tataru-Zworski [9] for semiclassical operators). The potential growth/concentration of the quasimodes of a semiclassical operator is of great interest due to the connection to Quantum Mechanics. It is from Quantum Mechanics that we get the important set of motivating examples,here ∆ g is the (positive) Laplace-Beltrami operator associated with the metric g. We can transition between this picture and the usual eigenfunction picture of Quantum Mechanics by dividing the eigenfunction equationwhere P is as in (1) with a potential term of h 2 V 0 (x) − 1. Therefore the higher eigenvalue asymptotics of eigenfunctions of Quantum Mechanical systems corresponds to the h → 0 limit in semiclassical analysis. When V 0 (x) = 0 this problem reduces to estimating the size of Laplacian eigenfunctions restricted to a submanifold. A complete set of estimates for Laplacian eigenfunctions on compact manifolds is given by Burq, Gérard and Tzvetkov [4].A