The killings come a month after a pregnant woman was beaten to death with bricks by members of her own family for marrying the man of her choice.
Maafia Bibi, 17, and her 31-year-old husband Muhammad Sajjad were attacked with a knife by Bibi’s father, her two uncles, grandfather and mother on Thursday night after inviting the couple to Bibi’s parents’ home.
The murders took place in a village which is part of Daska town, 162 kilometres (100 miles) east of the capital Islamabad.
“Bibi’s parents invited Muhammad Sajjad and his wife to their house to settle the dispute, but hit them both with a sharped-edged knife, killing them both,” district police chief Gohar Nafees told AFP.
He said that the couple had received blows to their heads.
Bibi’s parents, uncles and grandfather admitted killing them in the name of honour, saying they were being insulted, Nafees said.
Her parents were unhappy with the marriage, which took place on June 18, because Sajjad was already married to another woman, he added.
“Police arrested Bibi’s parents, uncles and grandfather,” Nafees said, after the family’s neighbours told police about the incident.
Many Pakistani women have no say in who they marry and disobeying the wishes of relatives is believed to bring shame on the whole family.
In May, Farzana Parveen, 25, who was three months pregnant, was bludgeoned to death outside a court in the eastern city of Lahore by family members in a case which made headlines around the world.
She was at the court to testify in defence of her husband, who was accused by her relatives of kidnapping her and forcing her into the marriage.
Last year 869 women died in so-called “honour killings” according to the independent Human Rights Commission of Pakistan.