2 deleted 10 characters in body edited Dec 18 '18 at 16:29 Henrik Schumacher 67.3k55 gold badges9696 silver badges185185 bronze badges For polynomial expressions @Buddha_the_Scientist's suggestion Variables will work. For more general expressions expr = x^2 + y^3 + z DeleteDuplicates@Cases[expr, _Symbol, \[Infinity]]∞]  Should do the trick in most situations. For polynomial expressions @Buddha_the_Scientist's suggestion Variables will work. For more general expressions expr = x^2 + y^3 + z DeleteDuplicates@Cases[expr, _Symbol, \[Infinity]]  Should do the trick in most situations. For polynomial expressions @Buddha_the_Scientist's suggestion Variables will work. For more general expressions expr = x^2 + y^3 + z DeleteDuplicates@Cases[expr, _Symbol, ∞]  Should do the trick in most situations. 1 answered Dec 18 '18 at 9:36 mmeent 2,25266 silver badges1414 bronze badges For polynomial expressions @Buddha_the_Scientist's suggestion Variables will work. For more general expressions expr = x^2 + y^3 + z DeleteDuplicates@Cases[expr, _Symbol, \[Infinity]]  Should do the trick in most situations.