Neck proprioceptive input, as elicited by muscle vibration, can produce destabilizing effects on stance and locomotion. Neck muscle fatigue produces destabilizing effects on stance, too. Our aim was to assess whether neck muscle fatigue can also perturb the orientation in space during a walking task. Direction and amplitude of the path covered during stepping-in-place were measured in ten blindfolded subjects, performing five 30 s-stepping trials before and after a 5 min-period of isometric dorsal neck muscle contraction against a load. Neck muscle EMG amplitude and median frequency during the head extensor effort were used to compute a fatigue index. Head and body kinematics was recorded by an optoelectronic system and stepping cadence was measured by sensorized insoles. Prior to the contraction period, subjects normally stepped on the spot or drifted forwards. After contraction, some subjects reproduced the same behavior, whereas others reduced their forward progression or even stepped backwards. The former subjects showed minimal signs of fatigue, the latter ones marked signs of fatigue, as quantified by the dorsal neck EMG index. Head position and cadence were unaffected in either group of subjects. We argue that the abnormal fatigue-induced afferent input originating in the receptors transducing the neck muscle metabolic state can modulate the egocentric spatial reference frame. Notably, the effects of neck muscle fatigue on orientation are opposite to those produced by neck proprioception. The neck represents a complex source of inputs capable of modifying our orientation in space during a locomotor task.