In principle, yes.
You would export your family tree from Ancestry as a gedcom. You would them go through WikiTree’s import process. This link will start you on the process. https://www.wikitree.com/wiki/Special:UploadGedcom
The exported file must end in “.ged” for the process to work. Sometimes the file gets saved as a “.txt” file which will not be imported. This file can be renamed by replacing the “.txt” with “.ged”.
The import is limited to a file of 5,000 individuals. If your family tree is larger than this you will need to split the file into smaller parts, for example you could export the ancestors of each grandparent separately.
It get familiar with the process it recommended to start with a smaller file.
It may be useful to search g2g for “gedcom“ to get a sense for some of the issues. In reading g2g comments you should expect a fair amount of work as you will need to compare each person in the file with possible duplicates. The upload leaves a lot of gedcom-related “artifacts,” commonly referred as “gedcom junk,” which should be removed as they do not add useful information to the profiles.
Personally, I have never done it. After reading comments about the process, I don’t anticipate doing it. I am sure others have a different opinion, and have done it successfully.
