Difference between tour operator and Travel agent?

A travel agent is someone who can book your travel details - flight, hotel, transportation and even tours, based on your requirements. Their responsibility is to organize your entire vacation, or as much of it as you like.

A tour operator is just someone who operates a business that provides tours of a certain area or series of attractions. They will organize and schedule tours for people, and will provide the guide. Their responsibility does not normally go beyond that.