Banana is one of the most important agricultural products of Ecuador. It relies on intensive monoculture cropping systems with a large volume of standing biomass and large amounts of residual biomass that can be used for carbon sequestration. This study was performed (1) to quantify the yearly residual biomass generation, (2) to quantify the carbon stock of standing banana biomass, (3) to estimate the carbon sequestration potential by using the residual biomass generated yearly, and (4) to propose a biomass prediction model for banana crops in Ecuador. The study was conducted between March 2018 and January 2019 in the three main banana-producing provinces of Ecuador (Los Ríos, Guayas, and El Oro). Samples of rachis, pseudostem, leaves, and flowers from 36 banana plants of the variety Musa AAA Cavendish were taken for laboratory tests. Physical measurements such as height, circumferences, number of leaves, and weights were determined for the 36 plants. Results showed an average residue-to-product ratio of 3.79 and a country's yearly biomass generation of 2.65 Mt on a dry basis. The carbon stock of the standing biomass was estimated as 4.18 ± 1.02 Mg/ha, 5.44 ± 0.96 Mg/ha, and 5.13 ± 1.11 Mg/ha for Los Ríos, Guayas, and El Oro, respectively. The estimated carbon abatement capacity of the residual biomass is 3.92 MtCO2/year. Three biomass estimation models were developed in Python®, using the data collected in this study and least squares fitting for exponential models of the form: Y = AXn + C. The models showed good prediction capacity for Ecuadorian banana plants, with R2 up to 0.85. It is expected that this study could serve as the basis for studies on developing sustainable conversion processes of banana residual biomass.