Rough neutrosophic multisets are an improved model of generalization pf neutrosophic multisets represented within the Pawlak’s boundary set of information: lower and upper approximation. The concepts of rough neutrosophic multisets can be easily extended to a relation, mainly since a relation is also a set, i.e. a subset of a Cartesian product. This paper establishes an axiomatic definition of rough neutrosophic multisets relation of Cartesian product over a universal set. Some of the operations and properties of rough neutrosophic multisets, such as max, min, the composition of two rough neutrosophic multisets relation and inverse rough neutrosophic multisets relation, are studied with a proven condition. An algorithm of rough neutrosophic multisets relation is also presented as a step followed to obtain the rough neutrosophic multisets relation. Successful analysis using rough neutrosophic multisets relation theory is represented by the illustrative example of expert opinion about automobile popularity. In conclusion, with a specified condition in uncertainty information, rough neutrosophic multiset relations are generalized in terms of the relation properties of a rough fuzzy relation, rough intuitionistic fuzzy relation, and rough neutrosophic relation over universal. Subsequently, their properties could also be examined.