Is Kim Cattrall the sister of Victoria Principal?

No. They are not sisters.

Victoria Principal was born in the United States whereas Kim Cattrall was born in England, then on to Vancouver, Canada, then to New York, and finally Los Angeles. She is currently doing theater in London.

Victoria Principal has one sister (named Kim), her parents' names were/are Victor and Ree. Most people are unaware that Victoria is of Hispanic lineage.

Kim Cattral has one sister, her parents' names were/are Dennis and Shane.

Kim Cattrall and Victoria Principal are not related at all.