I was taught that when interfere is followed by in, it means to get involved in something that doesn't concern you; when followed by with, it means to prevent something from being done. And this is confirmed by British English speakers on the other sources I have read.
However, when I looked up this word in Dictionary.com, I just found this entry: 2. to take part in the affairs of others; meddle (often followed by with or in ).
Is this a difference between American English and British English? As an American English speaker, will you also use interfere + with (as it says in Dictionary.com) when you are trying to express, for example, "Don't interfere in other people's business"?
Best Answer
In the case of, for example, someone else's life, you can either interfere in or with. The former is critical of the fact that you meddled at all. The latter is critical of the results of your meddling.
OP's definition of interfere in is correct - it means to get involved (usually, in matters that others think don't concern you).
To interfere with means to disrupt. Wave patterns, for example, can interfere with each other. This means they are mutually disruptive. Whilst it's true that interfering in someone else's affairs may be disruptive, it needn't be. But if you interfere with their affairs, you're definitely having a bad influence.
There's also the idiomatic usage of a paedophile interfering with a victim, which normally refers specifically to touching a child's genitals. I think in this case the thing being disrupted is the child's (future) sexual identity, but most of us would prefer not to dwell on the exact meaning there.