You Do Need power plug adapter while traveling from Lebanon to Gambia.

Here is Why You Need An Adapter

The outlet and plug type used in Gambia is G and in Lebanon are C, D and G. This is how they look like.

Lebanon

In Lebanon, outlets of type C, D and G are in use.

Type C

Type D

Type G

Gambia

In Gambia, outlets of type G are in use.

Type G