No; in the US, for example, Part 15 devices are, I think, limited to a maximum of 1W transmitted power at 2.4GHz, and 4W of EIRP (effective isotropic radiated power). i.e. maximum antenna gain of 6dBi at full power.

For fixed, point-to-point installations there is a special rule in effect: you can get more EIRP by having higher gain antennas as long as you back off the power; e.g. you can drop down to 22dBm (159mW) but have a 30dBi antenna and get 52dBm (159W) of EIRP.

A 30dBi antenna at 2.4GHz is, by the way, something like a 1.5 meter diameter parabolic grid.