The optimal ripeness stage for processing and marketing fresh-cut mangoes (Mangifera indica ‘Kent’) with best quality and maximum shelf life was determined. The initial ripeness stage selection was based on whole fruit firmness because this quality attribute was more reliable in predicting fresh-cut shelf life than flesh color or soluble solids content (SSC). Overall, the visual quality deteriorated differently and at different rates among ripeness stages. The shelf life, based on subjective visual evaluation, was 10, 7, and 5 days for ripeness stages corresponding to an average flesh firmness of 35, 30, and 25 N, respectively, and was mainly limited by desiccation and development of off-odor for the two firmer ripeness stages or symptoms of edge tissue damage and spoilage for the least firm stage. The slices from fruit with the highest initial firmness remained firmer during storage, had the lowest pH and SSC to titratable acidity (TA) ratio, and had the highest contents of volatile ketones and esters. The softest slices had the highest pH, SSC:TA ratio, and total ascorbic acid (TAA) content, as well as the lowest TA and highest volatile aldehyde and alcohol contents. Intermediate firmness slices had intermediate pH, SSC:TA ratio, color, and TAA content. Also, they had less volatile alcohols and aldehydes than slices from riper fruit but had similar content of esters as slices from the less ripe fruit. Therefore, based on the results from this study, an initial firmness of 30 N is recommended to process mangoes into fresh-cut slices because it assures the best quality and maximum shelf life based on textural, visual, and compositional attributes.