The Battle of Las Guasimas was the first true clash of arms in the Cuban campaign of the Spanish-American War.

A contingent of Spaniards, having fought a skirmish with American landing forces near Siboney on June 23, had retired to their lightly entrenched positions at Las Guasimas and repulsed American and Cuban raids. The task of dislodging the enemy fell upon General Wheeler, in overall command of the Rough Riders volunteer cavalry, 1st Regular Cavalry , and 10th Regular Cavalry , who marched his force out from Siboney the next day.

The battle commenced with the opening volley of American artillery. Spanish infantry quickly returned fire, peppering advancing American regiments with rifle shots. Despite the enemy's bright white uniforms, many American troops had difficulty locating Spanish soldiers, whose 1893 Mauser rifles fired modern smokeless propellants. Heavy foliage resulted in light casualties on either side.

Faced with a stubborn American advance, the Spanish began withdrawing in the direction of Santiago. Clearing the ridge, the Americans charged Spanish entrenchments. The last of the Spaniards retreated.

The American force briefly occupied Las Guasimas in anticipation of a counterattack that never came. Finding the position of minimal strategic importance, they buried their dead and withdrew, plagued by minor outbreaks of influenza.