Can a 19 year old be adopted in Ontario?

It is allowed:

http://blog.separation.ca/?p=637

But what are the chances if it happening? Most people want to adopt babies or very young children. They really don't want to adopt an adult.

Can you expand on why you want to know about this? I was assuming it was an issue of inheritance.

If you are expecting some family to adopt you out of the blue, it is unlikely to happen. Families are not going to be looking for an adult to adopt. But if you are involved with a family and want to be adopted by them it is possible.