<p>Understanding the deformation of microchannels is critical for designing microfluidic devices made of soft materials and operating under significant pressure gradients. This study aims to establish an analytic elastic model for the deformation of a shallow microchannel under the action of inner pressure that includes the geometrical parameters of the whole device. By considering a rectangular prism-shaped polymeric block with a straight channel on a rigid substrate, the stress, strain, and deformation of the channel’s roof are analyzed in a plane deformation framework. The outcomes illustrate that deformation is influenced by elastic and geometric variables. This model allows qualitative and quantitative predictions of the deflection in the roof of a microchannel. The model is tested experimentally with a flowing train of droplets, finding a good quantitative agreement. However, qualitative differences might suggest a non-negligible effect of the drops in the overall pressure-flow rate relationship.</p>