Confinement effects on the axial performance of reinforced concrete (RC) columns have been long recognized by the international research and practice community. The application of such effects has been incorporated in two international codes of practice, ACI 318-19 and EC2. However, in Vietnam there have been a very limited number of experimental studies that have been published nationally. This paper presents an experimental study on the structural performance of reinforced concrete (RC) circular columns. Four batches consisting of 16 column specimens, which had the same dimensions but were cast with four different concrete grades and detailed with different spacings of stirrups, have been gradually loaded to failure using load-controlled procedure. The test data revealed that increasing the stirrup ratio can enhance the structural performance of the column specimens. The test data have also been compared with the prediction by the Mander’s concrete model in terms of peak axial stress to evaluate the confinement effects on concrete material. Several interesting aspects of the test results have also been discussed, which set a concrete base for recommendations for design and detailing of RC circular columns.