In this article, polyamide 6 (PA6)/clay nanocomposites, PA6/polyethylene grafted maleic anhydride (PE-g-MA) blends, and PA6/PE-g-MA/clay nanocomposites were prepared and their gasoline permeation behavior and some mechanical properties were investigated. In PA6/clay nanocomposites, cloisite 30B was used as nanoparticles, with weight percentages of 1, 3, and 5. The blends of PA6/PE-g-MA were prepared with PE-g-MA weight percents of 10, 20, and 30. All samples were prepared via melt mixing technique using a twin screw extruder. The results showed that the lowest gasoline permeation occurred when using 3 wt % of nanoclay in PA6/clay nanocomposites, and 10 wt % of PE-g-MA in PA6/PE-g-MA blends. Therefore, a sample of PA6/PE-g-MA/clay nanocomposite containing 3 wt % of nanoclay and 10 wt % of PE-g-MA was prepared and its gasoline permeation behavior was investigated. The results showed that the permeation amount of PA6/PE-g-MA/nanoclay was 0.41 g m−2 day−1, while this value was 0.46 g m−2 day−1 for both of PA6/3wt % clay nanocomposite and PA6/10 wt % PE-g-MA blend. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40150.