Replacement of industrial byproducts as the main components of concrete has gained the attention toward the environment in reducing the raw material consumption. Fly ash (FA) cenosphere is one such industrial product used in the concrete as a partial or full replacement of fine aggregate, which can be able to use for non‐structural applications. Whereas for structural applications, reinforcement in the concrete and their bond behavior is an essential factor that influences its structural behavior. Hence, this study explores the bond behavior of plain and deformed rebar, 10 and 12 mm, respectively, in concrete containing 0%, 25%, 50%, 75%, and 100% FA cenosphere as fine aggregate. A pull‐out test is performed to study the bond behavior experimentally and the results show that the bond strength decreases with increase in the diameter of the rebar irrespective of concrete's compressive strength. The deformed rebar showed a better performance than the plain rebar with an average bond stress of nearly 60%. Finite element analysis has been performed using ANSYS‐ 2022R2 to validate the experimental results with simulated results in which the error percentage is in line with good results.