Aseko is one of the woredas in the Oromia Region of Ethiopia. It is named after the administrative center of the woreda, Aseko. Part of the Arsi Zone, Aseko is bordered on the southwest by Chole, on the northwest by Merti, on the north by the Mirab (West) Hararghe Zone, and on the east by Gololcha.
The altitude of this woreda ranges from 1000 to 2900 meters above sea level; the highest mountains include Weranbus, Abakoro and Dao. Rivers include the Arba, Dagnam Yelew and Bagdo. A survey of the land in this woreda shows that 19.2% is arable or cultivable, 17.9% pasture, 17.1% forest, and the remaining 45.7% is considered swampy, mountainous or otherwise unusable. Arbagugu State Forest is a local landmark. Coffee, khat, bananas and flax are important cash crops.
Industry in the woreda includes one grain mill and some mining, as well as 83 licensed traders of whom 71% were retailers, 26.5% wholesalers and 2.5% service providers. According to the Government of Oromia, "Aseko is the [most] disadvantaged district in industrial activities in Arsi zone." There were 13 Farmers Associations with 9669 members. Aseko has no reported roads, and is reportedly only accessible during the dry season; due to this inaccessibility, the woreda was largely excluded from rural development programs between 1974-1984. However, 27 kilometers of road connecting Abomsa in Merti to Aseko was reported as under construction in 2005. About 19% of the total population has access to drinking water.
The 2007 national census reported a total population for this woreda of 84,112, of whom 42,399 were men and 41,713 were women; 3,988 or 4.74% of its population were urban dwellers. The majority of the inhabitants said they were Muslim, with 62.83% of the population reporting they observed this belief, while 36.89% of the population practised Ethiopian Orthodox Christianity.