Laura Coward told friends she was taking her daughter Amber Lucius stargazing, days after her divorce from Amber's father Duane Lucius had been finalised.
But instead she drove the little girl to a remote location 60 miles north of Calgary, in Alberta, Canada, and slipped her prescription sleeping pills.
With Amber unconscious Coward set fire to her SUV with her daughter inside.
A post mortem found Amber died of a combination of hypothermia, smoke inhalation and carbon monoxide posioning.
A handwritten note was found on the outside of the burnt-out car's driver side door which read: "Help me. It was an accident. Locked keys in."
Coward, 50, was arrested two days after her daughter was reported missing, in August 2014.
She was initially charged with first degree murder but eventually pleaded to second degree murder in February.
Justice Scoot Brooker sentenced Coward to life in prison on Friday, saying her punishment must "reflect society's disgust and outrage."
Three days before her murder, Amber's parents' divorce had been finalised, with Duane had won full custody of their daughter.
Justice Scott Brooker said Coward's sentence must reflect "society's disgust and outrage."
“In murdering your own daughter you have committed a vile and evil crime,” he said.
“This court must express society’s disgust and outrage to denounce your evil act.”
"Amber was completely vulnerable to and trusting of her mother.
"It was the ultimate betrayal and breach of trust for Ms. Coward to kill her daughter."
Although he gave credit to Coward's for pleading guilty, he also noted the mother had never explained her motive for killing her daughter.
He concluded the only reason she committed such a crime was to "get back" at her ex-husband, Amber's father.