Yes - you can deduct interest on a timeshare if it is deeded and recorded in public records and the mortgage is recorded and secured by the financed property.
If you rent out the timeshare during the year, you must also use it as a home for more than 14 days, or more than 10% of the number of days it is rented. You count your days of use and the days of rental only during the time you have a right to use it or to receive any benefits from its rental.
Note:
Here's how to enter your mortgage interest statement in TurboTax:
No. You will not normally be able to deduct the interest paid if your timeshare week is through a long-term lease, also known as a “right-to-use” or “points-based” arrangement.
Your timeshare can carry the same tax deductions as a house, as long as it's a deeded real estate interest.
You can deduct interest on a timeshare if it is deeded and recorded in public records and it meets all the requirements for deducting mortgage interest.