Alexsandr Dyachenko (born 17 October 1983) is a Kazakh former professional road bicycle racer, who rode professionally from 2004 to 2006 and 2008 to 2015, for the Capec, Ulan and Astana teams.

In 2012, Dyachenko put in a solid performance at the Tour of Turkey, where he finished second overall, but the original winner Ivailo Gabrovski tested positive for erythropoietin (EPO). In October, it was announced that Gabrovski was stripped of the title, which went to Dyachenko.