A century by Nawroz Mangal proved decisive as the Afghans reached their target in the 34th over after Scotland had posted 199 for eight in the ICC World Cricket League Championship clash in the United Arab Emirates.
Richie Berrington had top-scored for Scotland with 51 but Afghanistan started well in their innings and Mangal hit six maximums in an unbeaten 112 to take the game beyond the Scots.
Scotland remain second in the table behind Ireland on 11 points but the Netherlands and UAE now have a game in hand and are just one point behind. Afghanistan have nine.
The top two nations automatically qualify for the 2015 World Cup.