Egyptian Occupation of Palestine
The UN Partition Plan for Palestine was a proposal to divide Mandatory Palestine into separate Jewish and Arab states. On May 15, 1948, the British Mandate officially ended, and the Jewish community declared the independence of the State of Israel. The Arab states rejected the plan and launched a military invasion. When the war ended, Egypt annexed the Gaza Strip, which had been designated for the Arab state under the UN plan. This annexation lasted until 1967, when Israel took control of the Gaza Strip during the Six-Day War.
During this period, 1948-1967, Egypt issued stamps for use in Gaza strip. From 1948 up to 1959, Egyptian stamps overprinted "Palestine" were in use. Here is an example of an overprinted Egyptian stamp shows the map of Gaza strip on FDC cancelled in Gaza, 1957.

From 1960 until 1967, permanent stamps with inscription "Palestine" were issued for Gaza. Here are stamps from this period on FDC cancelled in Gaza, 1960.

The 1960-1967 stamps were the same design as the stamps of Egypt (called UAR in this period) except the inscription "Palestine" and different colours. Here is an example:

Note: between years 1948-1960, the Gaza Strip was officially governed by "All-Palestine Government", a puppet government controlled by Egypt.