Can I claim the Canada Caregiver Amount if I am the legal guardian but not the biological parent of the infirm child?

Yes, you can claim the Canada Caregiver Amount if you are the legal guardian but not the biological parent of an infirm child, provided that you meet all the eligibility criteria set by the Canada Revenue Agency (CRA).

Check for more information here at the CRA website: Canada caregiver credit - Canada.ca (opens in a new tab)