Summary: The stability of linear neutral delay-differential systems with a single delay is investigated. In terms of solvability of a matrix Lie algebra, new simple delay-independent stability criteria are presented. The new criteria break through the limitation of \(\|C\|<1\), \(\rho (|C|)<1\) or \(\rho (|N|)<1\) in the existing stability criteria and thus lead to the asymptotic stability of neutral systems with a single delay in the case of \(\|C\|\geq1\), \(\rho (|C|)\geq 1\) and \(\rho (|N|)\geq 1\). Finally, two examples demonstrate the effectiveness of the new criteria.