Three gas holdup models are developed that correspond to different flow regimes in a 15.24-cm-diameter semibatch bubble column filled with various fiber suspensions. Three different perforated plate aerators are used and have open area ratios (A) of 0.57%, 0.99%, and 2.14%. Rayon fiber suspensions with lengths (L) of 3, 6, and 12 mm and cellulose fibers are used to form the fiber suspensions over a range of fiber mass fractions up to 1.8%. The models reproduce most of the data within ±15%. A limitation of the current models, due to limited experimental data, is that the model coefficients and exponents vary with aeration plate open area ratio and column diameter.