Soamanonga is a rural municipality in southwest Madagascar. It belongs to the district of Betioky Sud, which is a part of Atsimo-Andrefana Region. The population of the commune was estimated to be approximately 9,000 in 2001.

Only primary schooling is available. The majority 65% of the population of the commune are farmers, while an additional 35% receive their livelihood from raising livestock. The most important crops is rice but also mais and pistachios are important agricultural products for this municipality. Services provide employment for 5% of the population.

In Ankinany, a fokontany (village) of this municipality, coal deposits were discovered in 2007.

23°52′S 44°47′E / 23.867°S 44.783°E / -23.867; 44.783