Inductance in transmission line
Two parallel wires will have both self-inductance and mutual inductance. The self inductance gives rise to an "opposing" voltage when there is a change of current: -

\$V=-L\dfrac{di}{dt}\$

So if you try and pass a current through a wire there will be a "back emf" that opposes that current (that's the point of the negative sign). For a large value of inductance the change in current is restricted more than when the inductance is small.

Likewise, when there are two parallel wires, the change of current flow in one wire will give rise to an emf in the other wire: -

\$V=-M\dfrac{di}{dt}\$

The negative sign here implies that if the induced emf caused a current to circulate in the coupled coil, that current would create a magnetic flux that opposes the originating flux.

For two wires of self inductance L1 and L2 and sharing a coupling, M = \$k\sqrt{L_1L_2}\$

The "k" represents the coupling factor and can be 0 (no coupling) or 1 (full coupling).

You also mention transmission lines but this is where there can be confusion; it could be simply that you mean parallel wires or, it could be that you mean parallel wires in a power transmission or, you might mean a much more complex scenario where there are reflections from loads and standing waves. 

I'm just dealing with the simple case of self and mutual inductance of two parallel wires.