Data on genetic diversity and differentiation, as well as kinship between individuals, are important for the conservation of animal and plant genetic resources. Often genetic assignment is part of law enforcement of protected endangered species. The software GDA-NT 2021 is a new, freely available user-friendly Windows program that can be used to compute various measures of genetic diversity and population genetic differentiation. It further allows genetic assignment of individuals to populations and enables the calculation of kinship-coefficients and genetic distances among pairs of individuals within populations. GDA-NT 2021 specifically computes the alternative measures for population differentiation Dj and the standardized FST of Hedrick. It has more options to compute exclusion-probabilities in assignment tests, enables self-assignment tests for variable groups of individuals, and allows for information on geographic positions to be accounted for while using permutation tests to assess statistical significance.