A resonator having an effective spring constant (kz) and comprising a beam having a beam spring constant (kB) adapted to resonate in an oscillation direction, and extending at a non-zero angle (θ) to the oscillation direction, wherein the resonator has a predetermined geometry and is formed from one or more materials, the or each material having a coefficient of thermal expansion (CTE), the CTE of the or each material together with the predetermined geometry of the resonator causing θ to vary with temperature, such that the temperature dependence of the beam spring constant is compensated for, resulting in the effective spring constant of the resonator remaining substantially constant within an operating temperature range.