- A variable starts with the $ sign, followed by the name of the variable - A variable name must start with a letter or the underscore character - A variable name cannot start with a number - A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ ) - Variable names are case-sensitive ($my_car, $mycar, $myCar, $MYCAR, $MYcar are four different variables)

 
// Correct Syntax  ($variable_name = "Value";)
    $my_car = "BMW";
   
// Incorect Syntax
    my_car = "BMW";
    $7my_car = "BMW";
    $my&car = "BMW";