* Mildred Harris: His first wife. It's unclear if he had any in-laws from this marriage, as there's little information about her family.
* Lita Grey: His second wife, with whom he had two sons. Her family was involved in a messy and very public legal battle with Chaplin over custody and child support.
* Paulette Goddard: His third wife, with whom he had no children. There's less information about her family, and they were not as publicly involved in his life.
* Oona O'Neill: His fourth wife, with whom he had eight children. This is likely the family you are referring to. Her father was the famous playwright Eugene O'Neill, a Pulitzer Prize and Nobel Prize winner, so they were a very prominent family.
If you're interested in learning more about any of these families, I recommend looking for information about them specifically. For example, you could search for "Lita Grey's family" or "Oona O'Neill's family" to learn more.