diff --git a/tools/lammps-gui/lammpsgui.cpp b/tools/lammps-gui/lammpsgui.cpp
index 0e22adca30..f101006f61 100644
--- a/tools/lammps-gui/lammpsgui.cpp
+++ b/tools/lammps-gui/lammpsgui.cpp
@@ -1183,7 +1183,7 @@ void LammpsGui::start_lammps()
 
     // delete additional arguments again (3 were there initially
     while (lammps_args.size() > initial_narg) {
-        delete lammps_args.back();
+        delete[] lammps_args.back();
         lammps_args.pop_back();
     }