The nanoscratch behavior of nylon 66/SEBS-g-MA/clay ternary nanocomposites produced by different blending protocols with contrastingmicrostructures is studied by using atomic force and transmission electron microscopy. A standard diamond Berkovich indenteris used for scratching and a low load of 1 mN, along with a low sliding velocity of 1 lm s_1, are employed for this purpose. It is shownthat in order to resist penetration it is more important to have exfoliated clay in the continuous nylon matrix during nanoscratching thanto have the clay in the dispersed soft rubber domains. The results obtained also explain the preferred usage of ternary nanocompositescompared to binary nanocomposites, particularly nylon 66/exfoliated clay nanocomposites. This research extends current basic knowledgeand provides new insights on the nature of nanoscale processes that occur during nanoscratching of polymer nanocomposites. Criticalquestions are raised on the relationships between the penetration depth and material deformation and damage left behind the movingindenter.