Duhaime's Law Dictionary

Complementarity Definition:

The co-existence of two or more equally authoritative systems or sources of law.

A principle of construction of statutes.

For example, in NCJ Educational Services Ltd., the Federal Court of Appeal referred to the:

"... principle of complementarity reflected in ... the Interpretation Act ... (that) both the common law and the civil law are equally authoritative and recognized sources of the law of property and civil rights in Canada."


  • Interpretation Act, R.S.C. 1985, c. I-21, §8.1
  • NCJ Educational Services Ltd. v. Minister of National Revenue, 2009 FCA 131, [2009] 4 C.T.C. 290, 392 N.R. 11, 2010 C.L.L.C. 240-001 and 2009 CarswellNat 1095

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