Irish flag

The green on the flag represents the catholic/nationalist/republican communities, the orange represents protestant, and the white stands for hope and peace for each other.

about the flag

The national flag is a tricolour of green, white and orange vertical stripe with the green next to the staff. Some state that the third strip is gold not orange and it was taken from the gold harp on the original Green Flag.
This confusion arose in the 1916-22 period when the tricolour, was supplanting the Green Flag as the principal national emblem. Green and gold, the colours of the Green Flag, were regarded as the national colours throughout the nineteenth century and some of the homemade tricolours from the 1916-22 period were green, white and gold. There are also some songs from that period, which refer to 'green, white and gold' flags, but the symbolism of the green, white and orange dates from 1848.