Generally, the answer is no; US citizens are assigned a thirty-day visa-free stay in Macau upon arrival. European and Japanese citizens are allowed 90 days visa-free, and UK citizens six months. As with most countries, you will need six months of validity on your passport. If you intend to do business in Macau, as an increasing number of people do, you will need to apply for a business visa at the nearest Chinese consulate.
