The 98th Mixed Brigade was a unit of the People's Army of the Republic created during the Spanish Civil War.

On March 31, 1938, the unit launched a small offensive in the area of Esplegares, where they occupied some enemy positions and the town of Mocasilla, at the cost of some casualties.[n.

On May 7, the brigade launched an attack against the positions of "La Muela" and "El Morrón", managing to occupy the latter - after suffering numerous casualties - but it lost it shortly after.

It was subsequently transferred to La Iglesuela del Cid, but had to leave this locality on May 8, slowly retreating to the south.

In March 1939, the 98th Mixed Brigade supported the Casado coup, which brought the war to an end.