The Battle of Annual was fought on July 22, 1921, at Annual in Spanish Morocco, between the Spanish Army of Africa and Berber combatants of the Rif region during the Rif War. The Spanish suffered a major military defeat, almost always referred to by the Spanish as the Disaster of Annual, which led to major political crises and a redefinition of Spanish colonial policy toward the Rif.
In early 1921 the Spanish Army commenced an offensive into northeastern Morocco from the coastal regions they already held. The advance took place without extended lines of communication being adequately established or the complete subjugation of the areas occupied. In the course of the Spanish offensive, the Spanish commander General Manuel Fernández Silvestre had penetrated almost 130 kilometres into the enemy lines but during the hasty advances neither defensible forts nor accessible water supply points had been put in place. The territory newly occupied by the Spanish was garrisoned only by multiple small makeshift blockhouses (blocaos), each manned by a handful of soldiers (typically 12-20). These outposts were widely spread, typically located in high places, distant from water sources and lacking good communications with the main positions
On July 22, 1921, after five days of skirmishing, 5,000 Spanish troops occupying the advanced encampment of Annual were attacked by 3,000 Riff fighters. General Silvestre, who had arrived at Annual only the day before, decided upon a withdrawal along the line of the previous Spanish advance. A last radio message sent just before 5 a.m. advised Silvestre's intention to evacuate Annual later the same morning. At about 10am the garrison began to march in column from the encampment but confused leadership and inadequate preparation meant that any hope of an orderly withdrawal quickly degenerated into a disorganized rout. The Spanish conscripts, under heavy fire and exhausted by the intense heat, broke into a confused crowd and were shot down or knifed by the tribesmen. Only one cavalry unit, the Cazadores de Alcántara, kept in formation and was able to conduct a fighting retreat.
The riffi irregular forces were commanded by Muhammad Ibn 'Abd al-Karim al-Khattabi (usually known as Abd el Krim), a former civil servant at the Spanish administration in the Office of Indigenous Affairs in Melilla and one of the leaders of the tribe of the Aith Ouriaghel.
The overextended Spanish military structure in the Western Spanish Protectorate in Morocco crumbled. After the battle, the Riffian Berbers began to advance eastward, where they overran more than 130 Spanish blocaos. The Spanish garrisons were destroyed without mounting a coordinated response to the attacks. At the end of August 1921, Spain had lost all the territories it had gained in the area since 1909. General Silvestre disappeared and his remains were never found. According to one report, Spanish sergeant Francisco Basallo Berrcerra of the Kandussi garrison,  identified the remains of Silvestre by his general's sash. A Moorish courier from Kaddur Namar claimed that, eight days after the battle, he saw the corpse of the general lying face down on the battlefield.
At Afrau, on the coast, Spanish warships were able to evacuate the garrison. At Zoco el Telata de Metalsa in the south, Spanish troops and civilians were able to retreat to the French Zone. Spanish survivors of the battle retreated some 80 km to the sprawling fortified encampment of Monte Arruit, built between 1912 and 1916 and located south of Melilla. Here a stand was attempted under the leadership of General Felipe Navarro. As this position was surrounded and cut off from supplies, General Dámaso Berenguer Fusté, Spanish High Commissioner in the protectorate, authorized its surrender on August 9. The Rifeños reportedly did not respect the conditions of surrender and killed 3,000 Spanish soldiers. General Navarro was taken prisoner, along with 534 military personnel and 53 civilians who were ransomed some years later.
Melilla was only some 40 km away, but was in no position to help: the city was almost defenceless and lacked properly trained troops. The exhausted and demoralized survivors of Annual who reached Melilla were in no condition to effectively reinforce the existing garrison.  However, the Riffian tribal forces had largely dispersed following the capture of Monte Arruit, leaving Abd-el-Krim with insufficient men to lay siege to Melilla. In addition citizens of European nations were living in Melilla, and he did not wish to risk international intervention. Abd-el-Krim later stated that this was his biggest mistake.
Spain quickly assembled about 14,000 reinforcements from elite units of the Army of Africa which had been operating south of Tetuan in the Western Zone. These mainly comprised units of the Spanish Legion newly recruited in 1920, and Moroccan Regulares. Transferred to Melilla by sea, these reinforcements enabled the city to be held and Monte Arruit to be retaken by the end of November.
The Spaniards may have lost up to 20,000 soldiers at Annual and in subsequent fighting. German historian Werner Brockdorff states that only 1,200 of the 20,000 Spanish troops escaped alive, though this estimate of losses appears exaggerated. Rif casualties were reportedly only 800. Final official figures for the Spanish death toll, both at Annual and during the subsequent rout which took Riffian forces to the outskirts of Melilla, were reported to the Cortes Generales as totaling 13,192 killed.
Materiel lost by the Spanish, in the summer of 1921 and especially in the Battle of Annual, included 11,000 rifles, 3,000 carbines, 1,000 muskets, 60 machine guns, 2,000 horses, 1,500 mules, 100 cannons, and a large quantity of ammunition.Abd el Krim remarked later: "In just one night, Spain supplied us with all the equipment which we needed to carry on a big war." Other sources give the amount of booty seized by Rif warriors as 20,000 rifles (German made Mausers), 400 machine guns (Hotchkisses), and 120 to 150 artillery pieces (Schneiders).
The political crisis brought about by this disaster led Indalecio Prieto to say in the Congress of Deputies: "We are at the most acute period of Spanish decadence. The campaign in Africa is a total, absolute failure of the Spanish Army, without extenuation." The Minister of War ordered the creation of an investigative commission, led by General Juan Picasso González, which developed the report known as Expediente Picasso. The report detailed numerous military mistakes, but owing to the obstructive action of various ministers and judges, did not go so far as to lay political responsibility for the defeat. In all, the defeat is often thought of in Spain as the worst of the Spanish army in modern times.
The reasons for the crushing defeat may lie with Silvestre's tactical decisions and the fact that the bulk of the Spanish army was formed by poorly trained conscripts. Popular opinion widely placed the blame for the disaster upon King Alfonso XIII, who according to several sources had encouraged Silvestre's irresponsible penetration to positions far from Melilla without having adequate defenses in his rear. Alfonso's apparent indifference - vacationing in southern France, he reportedly said "Chicken meat is cheap" when informed of the disaster even though other sources render the quote as "chicken meat is expensive" when informed about the ransom demanded by Abd-el-Krim for the officials made prisoners in Mount Arruit- led to a popular backlash against the monarchy. The crisis was one of the many that, over the course of the next decade, undermined the Spanish monarchy and led to the rise of the Second Spanish Republic.