Guillermo Stevens Sierra (born 22 April 1960) is a Mexican tennis coach and former professional player.

He is also known by his nickname "Memo".

[1] Stevens was a collegiate tennis player for UT Austin prior to joining the professional tour, where he attained a career high ranking of 302 in the world.

[2] He was runner-up at the inaugural San Luis Potosí Challenger in 1980, qualified for the main draw of the 1982 Bordeaux Open and featured in the qualifiers for the 1983 Wimbledon Championships.

[3]