This invention relates to a stackable holder comprising a bottom (6) from which upright walls (2,3,4,5) are standing up. The bottom (6) is located at a distance from the under edges of the walls (2,3,4,5), whereas in these walls starting from the upper edges and under edges, substantially vertical slots (7) are made to receive the wall edges of the holder to be placed on it or under it or to receive connecting elements (8) to connect two adjacent holders. this invention further relates to a connecting element to be used in combination with such holders.