The objective of this study is to optimise the flotation process that separates crude oil and water from anionic polymer (GLP-100) via response surface methodology. Hence, a model was developed to describe the efficiency of oil removal under the influence of GLP-100 concentration, gas flowrate, and duration of flotation. Confirmatory experiments were performed to validate the model at a randomly selected point which was at 450 ppm of polymer concentration. At this point, the optimum values of the flotation parameters were recorded: 3 L/min of gas flowrate and 6 min of flotation time with 99 efficiency. The predicted values seemed to match the actual value with standard deviation 0.252. The outcomes prove that this model can be used to optimise the flotation process in the presence of GLP-100 polymer. © 2019, The Author(s).