My father wants to leave his house to my sister and I in his will. However, my step-mother says she has rights to the house because she is listed on the mortgage. Who actually owns the house?

Determining ownership of the house in this scenario depends on several factors, including the laws governing property ownership in your jurisdiction and the specific terms outlined in the mortgage and any other relevant legal documents. Here's a breakdown of the key considerations:

1. **Legal Ownership vs. Mortgage Listing:** Being listed on the mortgage does not necessarily confer ownership of the property. The mortgage is a financial agreement between the lender and the borrowers (your father and step-mother), outlining the terms of repayment for the loan used to purchase the house. Legal ownership, on the other hand, typically depends on how the property is titled and the laws of the jurisdiction.

2. **Title of the Property:** The title of the property is a legal document that establishes ownership. If the title is solely in your father's name, he would likely have sole ownership of the house, regardless of who is listed on the mortgage. However, if the title is held jointly with your step-mother, she may have a legal claim to part ownership of the property.

3. **Marital Property Laws:** Depending on the jurisdiction, marital property laws may come into play. In some places, assets acquired during a marriage are considered marital property, regardless of whose name is on the title or mortgage. This means that your step-mother could have a legal claim to a portion of the house's value, even if she is not listed on the title.

4. **Estate Planning and Wills:** Your father's intentions regarding the distribution of the house in his will are also significant. If he explicitly states his desire for the house to be inherited by you and your sister, that would carry significant weight in determining its ownership after his passing. However, if there are conflicting claims or legal complexities, the execution of the will may require legal assistance to ensure his wishes are carried out appropriately.

Given the complexity of the situation and the potential legal ramifications, it would be advisable for your father to consult with a qualified estate planning attorney who can review the relevant documents, assess the applicable laws, and provide guidance on how best to proceed. Resolving disputes over property ownership can be intricate and may require legal intervention to reach a satisfactory resolution for all parties involved.