U.S. Rules

• According to the federal Department of Homeland Security, your grandchild can immigrate with you as a dependent if he is under 21, not married and his unmarried parent is also immigrating with you as a dependent. If your grandchild does not meet these conditions, and you are not his legal guardian, he will have to immigrate on his own. Sponsorship is not an option.
  
  

Canadian Rules

• According to Citizenship and Immigration Canada, a grandchild's citizenship can be sponsored by a citizen if the citizen is not the legal guardian of the grandchild and the grandchild is orphaned, under 18 and not married or in a common-law relationship. Otherwise, your grandchild will need to immigrate on her own or with a parent.
  
  

U.S. Citizenship

• The best way for most grandchildren to become U.S. citizens is to come with their parents or immigrate on their own.
  
  If he is 18 or older and does not have a criminal record, he should fill out Form N-400, "Application for Naturalization," available online from the U.S. Citizenship and Immigration Services website (uscis.gov/n-400). The grandchild should begin learning American civics and U.S. history, and learn English if he does not already speak it.
  
  If he is a minor, he will need to immigrate with a parent.
  
  

Canadian Citizenship

• If your grandchild is over 18 and does not have a criminal record, she should fill out Form CIT 0002, available online from Citizenship and Immigration Canada (cic.gc.ca/english/pdf/kits/citizen/CIT0002E.pdf). Have the grandchild begin learning Canadian civics, history, and English or French, if needed.
  
  If she is a minor and her parents are immigrating, they will need to complete Form CIT 0003 (cic.gc.ca/english/pdf/kits/citizen/CIT0003E.pdf).