The behavior of Guatemalan Tyrannulet presumably is similar to that of Mistletoe Tyrannulet (Zimmerius parvus), but has not been described in much detail. It holds the tail up while foraging. Forages at all levels of the forest, but primarily in the middle and high canopy.

Typically encountered singly or in pairs. There are no published data on territorial defense, maintenance, or fidelity, or on home range size, for Guatemalan Tyrannulet.

Undescribed; Guatemalan Tyrannulet presumably is at least socially monogamous.

Guatemalan Tyrannulet tends to be solitary except when nesting.

No reports of predation on Guatemalan Tyrannulet.