A lens barrel module is disclosed to include a lens barrel unit and a flow path unit. The lens barrel unit extends along an axis and includes a peripheral wall that surrounds the axis and that has a first end adjacent to an object side of a lens assembly and a second end opposite to the first end and adjacent to an image side of the lens assembly. The peripheral wall defines an accommodation space configured as a series of accommodation sections for receiving the optical members. The flow path unit is formed in the lens barrel module and is in spatial communication with at least two of the accommodation sections. A lens assembly including the lens barrel module is also disclosed.