[4] The court held in favour of allowing battered woman syndrome to explain how the mental conditions for self-defence were present in this case, and Lavallee's acquittal was restored.

[2] The court ruled that the psychiatrist had given inadmissible testimony regarding past abuse that were unsubstantiated by hospital visits or police statements, and that the judge in that case had not properly instructed the jury regarding this.

[2] Justice Bertha Wilson, writing for the court, held that expert evidence is often needed when stereotypes and stigmatisation are inherent in a person's reasoning.

in R v Naslund, the Alberta Court of Appeal ruled that a woman who pled guilty to killing her husband after years of abuse had received too high a sentence.

Justice Sheila Greckol cited Lavallee in her majority opinion, stating that it is “beyond time for this Court to explicitly recognize that cases of battered women killing abusive partners involve unique circumstances that must be considered by the sentencing judge”.