Meaning of “I have no say in”

Question

I heard this in a movie and wondering what is the exact meaning and usage?

• I don't want to say anything (because I don't know about the matter).
• I know but I prefer not to say anything.
• I don't have right to say anything.

Answer 1

I have no say in the matter.

This means that I have no right to provide an opinion, or that my opinion won't be considered to be important in deciding the issue. The issue is entirely in the hands of others to decide.