The tech-heavy Nasdaq shed 21.33 points to 4,871.76.
The dollar rose by 1.42% against the euro, making one dollar worth €0.9543.
A strong dollar can hurt US companies’ profits, as they get less from their overseas earnings after currency conversions.
Additionally, the dollar’s strength makes it harder for firms to compete with foreign rivals, who may be able to offer similar products more cheaply.
The price of the US oil benchmark – West Texas Crude – fell by 4% to $45 a barrel, hurting shares in the sector.
Oil and gas driller Ensco fell by almost 6.6%, while rig owner Transocean fell almost 5%.