  In this paper we introduce the concept of $n$-Lie-isoclinism on non-Lie
Leibniz algebras. Among the results obtained, we provide several
characterizations of $n$-Lie-isoclinic classes of Leibniz algebras. Also, we
provide a characterization of $n$-Lie-stem Leibniz algebras, and prove that
every $n$-Lie-isoclinic class of Leibniz algebras contains a $n$-Lie-stem
Leibniz algebra.
