exists and is an alternate of . There are 32 letters in the full Greek Alphabet. They have been used since in the 8th to 9th century BCE. There are 32 letters in the full Greek Alphabet. They have been used since in the 8th to 9th century BCE. alpha, beta, gamma, delta, epsilon, digamma, stigma, zeta, heta, eta, theta, iota, yot, kappa, lamda, mu, nu, xi, omicron, pi, san, koppa, rho, sigma, tau, upsilon, phi, chi, psi, omega, sampi, sho. Source: