Muhammad Parvez and his son, Waqas, pleaded guilty to second-degree murder in the December 2007 slaying of 16-year-old Aqsa Parvez in Mississauga, Ontario, the Canadian Broadcasting Corp. reported.
The pair face automatic life prison sentences.
Police initially thought Muhammad Parvez, 60, had killed his daughter but it was revealed in court in Brampton that the 29-year-old son had strangled his sister.
"(Muhammad Parvez) decreed she should be murdered, but Waqas Parvez is no less guilty," prosecutor Mara Brasso said. "He had so many opportunities in those days to stop his father.
"The plan was in play at least two or three days before it happened. He never warned Aqsa. He never warned police. Even when they got to the home he obviously didn't falter on the threshold, on the doorstep and he carried on and murdered her."
Aqsa Parvez ran afoul of her father by pushing to be allowed to get a part-time job and to dress and act like other girls she knew. The Parvez family had moved to Canada from Pakistan five years earlier and the father required they adhere to his strict rules, including the wearing of a traditional headscarf called a hijab.
The teen's mother, Anwar Jan, told police her husband had said the killing was necessary because he was insulted by her behavior.
"My community will say, 'You have not been able to control your daughter.' This is my insult. She is making me naked," she quoted him as saying.