The action stoked fears of rising tensions in the Middle East and oil prices jumped in response.
The Dow Jones fell 40 points, or 0.2% to 17,678, while the broader S&P 500 dropped 5 points, or 0.2%, to end on 2,056.
The tech-focused Nasdaq closed 13 points lower, or 0.3%, at 4,863.
Oil prices surged on news of the airstrikes. Brent crude futures jumped $2.6 to hit $59.09 a barrel, while US crude settled $2.08 higher at $51.29 a barrel, having peaked at $52.48 a barrel earlier.
"Obviously the situation in Yemen is being used as the excuse for this pullback, which is a continuation of yesterday," Peter Cardillo, chief market economist at Rockwell Global Capital, told Reuters.
Among individual stocks, Sandisk fell 18% after the firm cut its outlook for revenues for both the first quarter of 2015 and the full year.
Yoga-attire maker Lululemon Athletica jumped 4.9% as revenues for the three months to 1 February rose 15.6% to $602.5m.
The dollar gained 0.8% against the euro, edging to â‚¬0.9188.
(Close): Stocks on Wall Street closed lower as global markets tumbled following news of airstrikes by Saudi Arabia and its allies on Yemen.