A leash assembly having a strap or leash that can be reeled or unreeled for walking animals. The assembly has a handle and a housing attached thereto in which the strap is arranged on a turnable roller device for being reeled or unreeled. The assembly also includes a brake key that can stop and prevent rotation of the roller device to restrict a part of the strap extending externally of the housing to a desired length. In addition, the assembly includes an exit opening through which the strap extends externally of the housing. Preferably, the exit opening is formed as a slit, and the slit has a central region along its longitudinal extension that has an enlarged opening porfion extending laterally from at least one side of the slit.