Germany and Italy performed territorial occupations in the years that preceded WWII.
The authorities in Nazi Germany implemented the "living space" policy. They justified the need of expanding its territory in order to enhance the living conditions of the superior German race and civilization. Moreover, they promoted a permanent removal of Central and Eastern Europeans that were considered non-Aryans and hence, subhumans. After the acquisition of many other small territories, the occupation of the demilitarized region named Danzig, in current Poland, triggered the start of WWII.
The fascist Italian state did not agree with the peace agreements after WWI as those had not fulfilled their territorial expectations. This government started an aggressive approach in foreign policy and also tried to expand their territories and to occupy new lands, for example in Greece.