An electrical connector assembly (1) includes a first connector (2) and a second connector (3) engageable with the first connector. The first connector has a first dielectric housing (20) defining a pair of receiving spaces (202), a number of first terminals received in the first housing and a pair of latches (24) retained in the receiving spaces. Each latch includes a retaining portion and a curved spring portion (242) connecting with the retaining portion. The second connector has a second dielectric housing defining a pair of recesses (34) on opposites outer sides thereof and a number of second terminals (32) received in the second dielectric housing. The spring portions of the latch securely engage with the corresponding recess of the second dielectric housing, whereby the first connector stably mates with the second connector.