There is provided splice trays and splice assemblies that include one or more optical fiber routing guides for optical fiber slack storage. The optical fiber routing guides are associated with individual or select groupings of splice holders in order to eliminate slack storage generally around the perimeter of the splice tray. Therefore, the optical fibers of one or a select number of splices may be routed separately from other optical fibers to enable technicians to more easily manipulate the fibers. In addition, optical fiber routing guides are included with a splice assembly in order to eliminate slack storage generally around the splice tray. The optical fiber routing guides additionally may define bend radiuses of between about 0.1 inch and about 0.5 inch. Therefore, splice trays and splice assemblies comprising the optical fiber routing guides may provide more convenient access and/or define smaller sizes compared to previous splice trays and splice assemblies.