Abstract: An extension ladder consisting of a lower ladder section and an upper ladder section secured to one another so that the upper ladder section can be extended relative to the lower ladder section using a ladder extension rope. Each ladder section has the same width and each has a pair of spaced stiles with rungs. A clutch member extends between the ladder sections and is movable between a locked position, for mounting the upper ladder section at a desired extension relative to the lower ladder section, and a released position. A clutch locking mechanism biases the clutch member into the locked position. The stiles of each ladder section has formations for securing the sections relative to one another, and enable the upper section to be extended and retracted in relation to the lower ladder section.