This review article explores the legislative differences across Canadian jurisdictions with respect to involuntary admission and treatment pending appeal. Some jurisdictions restrict involuntary admission for mental illness to when there is a risk for serious bodily harm or physical impairment. However, the majority of jurisdictions recognize non-bodily harms or substantial mental or physical deterioration as grounds for involuntary admission when other criteria are met. Once a person is involuntarily admitted, jurisdictions differ on how treatment is authorized and whether treatment can commence while a person contests a finding of incapacity to treatment to the courts. Some jurisdictions permit treatment pending appeal while others do not. This article compares Canadian jurisdictions’ mental health legislation and addresses discrepancies through the lens of the Canadian Charter of Rights and Freedoms and the Canada Health Act.