Technical Abstract: Maturity and fineness are important cotton fiber properties, as they can impact the fiber’s downstream processability and dye performance. Maturity and fineness are often indicated indirectly by the fiber’s micronaire. Maturity and fineness can be measured directly, but most available methods are slow and/or require expensive laboratory-only equipment. Much interest has been shown in new direct measurements of fiber maturity and fineness that could be applicable for both laboratory and at-line/field use. A program was implemented to determine the feasibility of using NIR systems (analyzers and measurement methods) to monitor fiber maturity and fineness in the laboratory. Well-defined cotton sample sets were measured on multiple bench-top and portable NIR systems in a conditioned laboratory, and their results compared. NIR instrumental, sampling, and operational procedures and protocols were established. Very good spectral agreement was observed between the NIR units. NIR measurements took less than 3 minutes per sample, and no sample preparation was required. The accurate measurement of fiber maturity by both bench-top and portable NIR analyzers/systems was demonstrated, indicating a very promising potential for cotton field analyses of maturity by portable units. Acceptable fiber fineness results were observed for the bench-top unit only, and additional samples will be required for improved portable NIR unit measurements.