如果持有美国绿卡去加拿大需要签证吗？

你可以到这个页面看一下：http://www.cic.gc.ca/english/visit/visas.aspUnited States citizens and permanent residents: You do not need a visa to visit or transit in Canada if you are a United States citizen or a person lawfully admitted to the United States for permanent residence who is in possession of their alien registration card (Green card) or can provide other evidence of permanent residence. 大意是如果持有绿卡（为合法的美国永久居民）则不需要签证