Married couple Imran and Farzana Ameen and their five children, aged five to 15, were reported missing earlier on Tuesday, West Yorkshire Police said.
Officers said the family were last seen on 5 October and are believed to have travelled to Turkey - though their "current whereabouts are unknown".
The children's welfare was the "primary concern", police said.
Police said officers were "working with relatives who are still in the UK" and that "lines of enquiry are currently being progressed with the Turkish authorities".
Assistant Chief Constable Russ Foster added: "We would urge anyone with information about the family's whereabouts to come forward and speak to police so the family can safely return to the UK.
"Any piece of information, no matter how small, could help the UK or overseas authorities to locate the family so that they can be safely returned home to their loved ones."
A missing family of seven from Bradford are believed to have travelled to Turkey, police say.