Discusses the challenges inherent in achieving desirable outcomes for separated asylum-seeking children and adolescents in Canada and suggests that existing children’s international law provides a useful guide but cannot guarantee that the best interests of children will be served. Includes discussion of the key provisions of the United Nation Convention on the Rights of the Child; the history of the concept of a child’s best interest; interpretation of the concept of best interests and its application to both public and private institutions; the weight given to the principle of best interests with respect to competing interests of justice and society; decision-making with respect to the principle of best interests and limitations on the range of outcomes; particular stipulations regarding children’s participation in decisions concerning their best interests; and difficulties determining good practices associated with the best interests of unaccompanied children. The best interests of separated children in Canada could be strengthened by the adoption of a national protocol of standards and practices and by creation of a children’s rights system that incorporates the Convention on the Rights of the Child into domestic law.