A dispensing device for dispensing a substance, for instance a pressurised metered dose inhaler (pDMI), comprises a housing in which the substance is receivable and which has a dispensing nozzle from which the substance is in use dispensed and a closure for releasable mounting on the nozzle for closure thereof. The closure comprises a cap member which is configured and arranged with respect to the nozzle such as to be capable of being slid over the nozzle in an intended orientation of the cap member and an unintended orientation of the cap member. In the intended orientation of the cap member the closure is securably mounted on the nozzle by sliding the cap member over the nozzle by a predetermined amount to a stationary position. The housing and the closure are configured and arranged with respect to each other such that the cap member cannot slide over the nozzle by the predetermined amount to a stationary position when in the unintended orientation thereby to indicate to the user that the closure is not correctly mounted on the nozzle.
