Summary: Associative rings are considered. By a lattice isomorphism (or projection) of a ring \(R\) onto a ring \(R^\phi\) we mean an isomorphism \(\phi\) of the subring lattice \(L(R)\) of a ring \(R\) onto the subring lattice \(L(R^\phi )\) of a ring \(R^\phi \). Let \(M_n(GF (p^k))\) be the ring of all square matrices of order \(n\) over a finite field \(GF(p^k)\), where \(n\) and \(k\) are natural numbers, \(p\) is a prime. A finite ring \(R\) with identity is called a semilocal (primary) ring if \(R/\operatorname{Rad} R \cong M_n (GF (p^k))\). It is known that a finite ring \(R\) with identity is a semilocal ring iff \(R \cong M_n(K)\) and \(K\) is a finite local ring. Here we study lattice isomorphisms of finite semilocal rings. It is proved that if \(\phi\) is a projection of a ring \(R = M_n(K)\), where \(K\) is an arbitrary finite local ring, onto a ring \(R^\phi \), then \(R^\phi = M_n(K\)’), in which case \(K\)’ is a local ring lattice-isomorphic to the ring \(K\). We thus prove that the class of semilocal rings is lattice definable.