It may or may not be important according to your weight and why you want it. The heavier you weigh, the thicker you want your mattress topper to be. If you are fairly heavy, you will not appreciate using a 2-inch thick topper. If you want to feel the memory foam effect, then get the thickest you can find if you are regarded as overweight or obese. You could go to 3-inch (#3, 4, 7, 9 and11 in our list) or even 4-inch (#1 and #6). If you are not particularly heavy, then thickness should be such an issue. Obviously, a 3-inch or 4-inch memory foam topper will give you more of the memory foam effect than a regular latex foam topper. However, many people simply want a mattress topper to soften up or harden their sleeping surface, and the memory foam aspect is irrelevant to them. The thickness may be important, so were we to recommend anything it would likely be 3 inches. However, many 2-inch foams are just as effective at keeping you cool and providing you with a comfortable sleeping surface. That’s why we include three of these on our list.