We study the parity of coefficients of classical mock theta functions. Suppose g is a formal power series with integer coefficients, and let c(g; n) be the coefficient of q n in its series expansion. We say that g is of parity type (a, 1 − a) if c(g; n) takes even values with probability a for n ≥ 0. We show that among the 44 classical mock theta functions, 21 of them are of parity type (1, 0). We further conjecture that 19 mock theta functions are of parity type ( 1 2 , 1 2 ) and 4 functions are of parity type ( 3 4 , 1 4 ). We also give characterizations of n such that c(g; n) is odd for the mock theta functions of parity type (1, 0).