The (A) over tilde (2)Pi(r) (0 0 0) <- (X) over tilde (2)Sigma(+) (0 0 0) system of a cold beam of barium hydroxide, BaOH, has been studied field-free and in the presence of a static electric field. Stark tuning of the low-J branch features in the (A) over tilde (2)Pi(3/2) (0 0 0) <- (X) over tilde (2)Sigma(+) (0 0 0) transition were analyzed to give permanent electric dipole moments, mu, for the (A) over tilde (2)Pi(3/2) (0 0 0) and (X) over tilde (2)Sigma(+) (0 0 0) states of 0.477(7) D and 1.43(4) D, respectively. The results are compared with other alkaline earth monohydroxides and values predicted using an electrostatic polarization model and ligand field theory. (C) 2011 Elsevier B. V. All rights reserved.