Acoustic wave techniques can provide a surface undergoing a high frequency (MHz to GHz) oscillation.  This surface oscillation is highly sensitive to interfacial conditions with attachment of mass to the surface or changes in the liquid environment resulting in frequency shifts and damping of the oscillation. It is also known that the degree of response of liquid phase acoustic wave sensors depends on the surface roughness and topography. In this presentation, an overview will be given of the physical principles of a range of acoustic wave modes and the conditions under which these modes can be applied to create sensors of the solid-liquid interfaces. Similarities between different types of acoustic wave device (quartz crystal microbalances (QCM), surface acoustic wave (SAW), Love wave and acoustic plate mode) will be emphasised and basic models of acoustic wave response will be described, including concepts of multiple modes in Love wave devices, frequency hopping and sensitivity, and layer-guided plate modes. The possible effects of wetting, interfacial slip, trapped mass and hydrophobicity on acoustic wave response will be discussed. In particular, the validity of the no-slip boundary condition and the effect of changes in hydrophobicity when a surface has small-scale texture will be considered. In the extreme case, the water repellence of a surface with high aspect ratio surface features is so amplified by the surface chemistry that droplets are effectively suspended on the tips of the surface features and roll easily. The implications of these types of superhydrophobic surfaces for acoustic wave responses will be discussed.