This work mainly deals with the sliding mode control for non-linear model of sloshing liquid in a container. Slosh coupled with container dynamics represents a class of underactuated systems with coupled non-linear equations. A pendulum model is used to model the lateral slosh. A linear sliding surface-based sliding mode control is derived. The reduced order system equation during sliding mode becomes non-linear when the non-linear system is constrained to the linear surface. Here a new method is proposed for the stability analysis of the reduced order non-linear system using Lyapunov stability theory. Simulations are carried out to validate the method. Experimental work is carried out to implement the designed sliding mode control strategy on the slosh-container system and corresponding results are also reported. Copyright © 2013 Inderscience Enterprises Ltd.