This paper presents a methodology for designing side slope liner systems to accommodate downdrag due to waste settlement. Settlement and downdrag along steep-lined slopes in landfills and other waste or mining containment facilities (e.g. heap leach pads, mine tailings impoundments) will occur to varying degrees during initial construction, waste placement, and post placement. Two key questions in this regard with respect to the design of the side slope liner system are: “how much downdrag will occur?” and “at what degree of slope inclination does downdrag become an engineering concern?” The little field monitoring and limited research that has been done on this subject indicates that at a slope inclination of perhaps 2H:1V (Horizontal:Vertical) or steeper, downdrag could be a significant concern, but it could occur on flatter slopes as well, depending on the forces and the relative interface shear resistances within the liner system. The methodology presented herein combines a slip interface above the primary geomembrane with an underlying high-strength geotextile that is anchored at the benches and side slope crest and that extends part-way down the slope to sustain tensile forces induced by downdrag. Finite difference analyses were performed that demonstrate the feasibility of this approach to meet design goals using commercially available geosynthetic material.