Americanisation is the a term used for the perceived influence America has on the culture of other countries, substituing local culture with something of an American culture. It is often used in a negative context.
One of the principle reasons for this is America's highly visible global brands (e.g., McDonalds) and widely distributed media output.
It is often used as a term for fears of cultural substitution and can be compared to American fears of America being changed to be more like Mexico.
See also: