Guilherme Peirão Leal (born 22 February 1950 in Santos) is a Brazilian billionaire entrepreneur.
He is the co-chairman of the board of directors of, and owns a 25 percent stake in, Natura, Brazil's leading manufacturer and marketer of skin care, solar filters, cosmetics, perfume and hair care products.
According to Forbes, Leal had a fortune worth roughly US$2.1 billion as of 2010.