Background Impaired balance is common in neurological disorders. Cervical dystonia is a neurological movement disorder affecting the neck. The effect of this aberrant head posture on physical function is unknown. Objectives To compare balance, mobility, gait and stepping reactions between ten people with cervical dystonia and ten control adults. Methods Spatiotemporal gait parameters and walking speed were assessed using a computerised walkway. Step length and time, time in double support and gait variability were calculated, then normalised to gait speed. Centre of pressure path length was assessed with eyes open and eyes closed to calculate a Romberg Quotient. Simple and choice reaction times were measured using customised apparatus while mobility was assessed by the timed up and go. Cervical spine range of motion was measured using a head mounted goniometer. Self-reported scales included Falls Self Efficacy Scale and Dystonia Discomfort Scale. Results There was a difference between groups for most outcome measures. The timed up-and-go and walking speed was slower (both P < 0.005) and the Romberg Quotient lower (P = 0.046) in cervical dystonia. People with cervical dystonia had lower falls self-efficacy (P = 0.0002). Reduced cervical range of motion was correlated with balance, stepping reaction time and mobility (all P < 0.05). Timed up and go was positively associated with stepping reaction time (P < 0.01). Dystonia discomfort did not impact function. Conclusions People with cervical dystonia displayed deficits in balance, gait and stepping reactions, and expressed higher fear of falling. Studies to further elucidate functional limitations and their impact on activity and participation in daily life are required.