There is provided a composition for improving memory, learning ability, and cognitive ability. It has been confirmed that a peptide having a C-terminal region ended to GAG had an effect of improving the memory. In order for the peptide to have the effect, it has been confirmed that the peptide should be a peptide of which the length consists of at least 4 amino acids. Further, it has been confirmed that a peptide of which the length of the peptide having the C-terminal region ended to GAG consists of 5 to 9 amino acids has the same effect. As a result, the peptide of the present invention can be used as the composition for improving memory, learning ability, and cognitive ability.