Paectes medialba is a moth in the family Euteliidae first described by Michael G. Pogue in 2013.

The costal area of the forewings is dark gray mottled with white scales and faint white dashes along the costa from just beyond the middle to below the apex.

The hindwings are white, with dark gray marginal shading.

The veins are highlighted with dark gray and the anal fold has a white and dark-gray striped pattern.

The species name is derived from the combination of the Latin terms medius (meaning middle) and albus (meaning white) and refers to the white medial area of the male forewing.