The Services of Supply (S. O. S.) was the support chain of the American Expeditionary Forces in France, England, Italy and the Netherlands during World War I.

The Services of Supply (SOS) of the American Expeditionary Forces (AEF) was established under the designation "Line of Communications," on July 5, 1917.

[1]: 11–13  The Line of Communications was judged by senior officers, including Colonel Johnson Hagood, who was in charge of the advance section, to be incompetent.

[3] The SOS remained in operation until July 19, 1919; some of its sections were transferred to American Forces in France and American Forces in Germany[1]: 57 On September 7, 1917, General John J. Pershing, the AEF's commander, directed that a ninety-day reserve of all classes of supplies be maintained by monthly shipments to reduce the impact of possible German submarine attacks.

Initially commanded by John F. Madden,[4] the Advance Section, headquartered at Neufchâteau, France, distributed supplies to the zone of operations.

[1]: 41 [3] Advance Section area included the French Departments of Nord, Pas-de-Calais, Somme, Oise, Aisne, Ardennes, Marne, Aube, Meurthe-et-Moselle, Meuse, Haute-Marne, Cote d'Or, Vosges, Haute-Saône, and Doubs and the Territoire de Belfort.

Its area comprised the French Departments of Morbihan, Côtes-du-Nord, Ille-et-Vilaine, Loire-Inférieure, Maine-et-Loire, Vendée, Deux-Sèvres, and Vienne.

Base Section Number 1 was discontinued on October 20, 1919; its personnel and units were assigned to American Forces in France.

Approximately 200,000 soldiers entered France through the two ports and cargo handling reached 350,000 tons a month in October 1918.

This base section, headquartered at Bordeaux, France, included the French Departments of Charente-Inferieure, Gironde, Landes, Lot-et-Garonne, Dordogne, and Charente.

Base Section Number 2 was discontinued on September 30, 1919; its personnel and units were assigned to American Forces in France.

[1]: 48 Base Section Number 5 was established on November 27, 1917, with headquarters in Brest, France, comprised the French Department of Finistère.

The section's territory covered the French Departments of Bouches-du-Rhone, Var, Alpes-Maritimes, Basses-Alpes, Vaucluse, Ardèche, Lozère, Aveyron, Tarn, Aude, Pyrenees-Orientales, Herault, and Gard.

Commanders included Brigadier General Charles Gerhardt[1]: 48, 72 Base Section Number 8 was established on November 4, 1918, with headquarters and only port in Padua, Italy.