Presently, the exponentially increasing cost of labor and construction materials have made it more challenging to meet the demand for shelter and low-cost housing. As a result, there is a need for alternative, cost-effective, sustainable materials and methods. One potential solution is the use of ancient building materials like earth or soil, which is cheap and abundant. Typically, soil has been practiced for centuries and is still used as walling material in the majority of the rural housing in Ethiopia. Despite the long practice and soil’s weak strength, there are still limited studies on the properties in stabilizing and conducting proper mix design or setting standards in our country. The purpose of this study is to assess the effect of plastic bottle and “Teff” straw fiber on building an interlocking compressed stabilized earth block. In this study, three samples of soil were selected in Bahir Dar City and were tested for shrinkage and sedimentation/bottle test along with Atterbereg limits and compaction laboratory tests. Among the varieties, the Gudo Bahir soil sample passed with a 1:18 cement to soil ratio. Then, “Teff” straw and plastic bottle fibers were prepared and mixed. A total of 150 sample interlocking compressive stabilized earth blocks (ICSEB) were casted with 30 samples for five types of blocks (Soil and cement only; Soil, cement and Teff straw; soil, cement, and “Teff” straw top up; Soil, cement and plastic fiber; and Soil, cement, rough edged plastic fiber types of blocks). Based on the experiment, “Teff” straw blocks resulted in a 4.08MPa with a water absorption of 9.6%, which is below the recommended setting of 15%, and water jet result of the ICSEB as nil or no sign of penetration on its 28th day curing age. The performance of the “Teff” straw top up block also showed a promising result as an alternative wall material for low cost house construction.