Duhaime's Law Dictionary

Interlineation Definition:

An addition of something to a document after it has been signed.

Such additions are ignored unless they are initialed by the signatories and, if applicable, witnesses (eg. wills).

In Williams on Wills, the authors wrote under the caption Interlineation:

"This is not confined to something written between the lines but is equally applicable to something inserted on the lines or carried in by a cross or asterix.

"Words written following the executed part of the will have been refused to be treated as an interlineation even when they completed an otherwise incomplete sentence in the executed part."

In Bagshawe v Canning, Justice Hannen wrote:

"I am not prepared to say that ... the word interlineation in the Act is to be confined to something written between the lines. Undoubtedly, that is its etymological meaning, or one of its meanings. But I think it has acquired a secondary signification, namely, the introduction of something into the will, and I think it would be equally an interlineation within the meaning of the Act if something were put into one of the lines written on the line."

Many jurisdictions provide for interlineations within their relevant wills statute. For example:

"(1) Subject to subsection (2), unless an alteration that is made in a will is made in accordance with the provisions of this Act governing the making of a will, the alteration has no effect, except to invalidate words or meanings that it renders no longer apparent.

"(2) An alteration that is made in a will is validly made when the signature of the testator and the subscription of the witness or witnesses to the signature of the testator to the alteration are made in the margin or in some other part of the will opposite or near to the alteration, or at the end of or opposite to a memorandum referring to the alteration and written in some part of the will."1


  • Bagshawe v Canning, [1888] 52 JP 583
  • Martin v. Martin, 165 NE 644 (1929)
  • Re Samson, 59 DLR (2d) 132 (1966)
  • Sherrin, C. H. and others, Williams on Wills, 8th Ed. (London: Butterworths, 2002), at page 151, ¶14.12
  • Wills Act, RSBC 1996, c 489, §17 [NOTE 1]

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