An object of this invention is to provide a sleep improvement composition, which contains theanine and other components and can be used safely by anybody on a daily basis without side effects. This object is attained by a sleep improvement composition comprising: (a) theanine; and (b) at least one component selected from the group consisting of chamomile, lavender, Saint John's wort, kawakawa, valerian, passion flower, tryptophan, .gamma.-aminobutyric acid, serotonin, melatonin, and cedrol.