Phyllodonta alajuela is a moth in the family Geometridae first described by J. Bolling Sullivan in 2014.

It is found in Costa Rica (Alajuela and Guanacaste provinces), possibly extending into Nicaragua.

The forewings are warm brown with prominent undulating antemedial and postmedial lines.

Both lines are black edged with lighter grayish scales proximally.

The reniform spot is small and black and forms a center of a gray circle.