I recognised the Holiday Fair tag. I know I had some toys like that in the 80s. Stuff that either belonged to my mom and her brothers that my grandparents held onto or came from the Salvation Army. We got a lot of toys there because we were poor.
Holiday Fair was a huge toy company in the 60s. They were based in Japan but also had toys marketed in the US. Not sure about other countries. They are most famous for Bradley Dolls.
It's just that when you look up Holiday Fair toys it's hard to get info on anything other than the Bradley Dolls because that's what people like to collect. When you google Holiday Fair mouse you get the chalkware coin banks and a few other stuffed mice that are a lot different from yours. I guess there really aren't many collectors of Holiday Fair stuffed toys. You might be the first person to photograph this toy for the internet. But these toys were common at one point. Although you aren't as likely to see them floating around secondhand in actual shops anymore because so much time has passed. I don't think that the company is still around either. But when I was a kid these were the musty things you picked up at thrift shops for a few cents. I've never seen this one though.
I had gotten it from a friend when I was little and when I asked her she had no clue where it was from. I'm gonna try to contact a few people around the internet about it but other than that I can't really do anything about this.