Functional programming is growing like crazy. There are functional programming conferences all over the world, and new ones pop up all the time.
You can filter the list by three factors: the location (continent), the quarter of the year it usually takes place in, and the language or technology. There's also a [NONE] value for the ones that don't have a value for that. For instance, general functional programming conferences don't have a specific language.
If you find a conference that is not on this list, let me know and I'll add it. Likewise if you find a mistake.