Answer:
Often called the Philippine Insurrection (in the US), or the War for Philippine Independence (in the Philippines), this was a conflict over the government and ownership of the Philippines.
The United States had just fought and won a war with Spain, and, as a prize, was awarded "ownership" of the Philippines, which had previously been a Spanish possession. However, many of the native Philippine people felt that they should have an independent country, and not be ruled by a foreign power (they didn't much care for the changing of their master, just that it was still an overlord). Thus, when the US brought in significant military force to occupy their newest prize, the local population began a revolution, attempting to oust the Americans.