  Spinor and twistor formulations of tensionless bosonic strings in
4-dimensional Minkowski space are constructed. We begin with a first-order
action that is equivalent to the Nambu-Goto action in the tensionful case and
that leads to a spinorial action in the tensionless case. From this spinorial
action, we find an alternative spinorial action useful for constructing a
simple twistor formulation of tensionless strings. The twistor formulation is
steadily constructed in accordance with a fundamental concept of twistor
theory. We investigate local internal symmetries inherent in the twistorial
action for a tensionless string and carry out some classical analyses of the
tensionless string expressed in a twistorial form.
