Mauresmo, 35, made the announcement on Twitter.
“Baby will be here in August ! #pregnant So happy,” she tweeted.
The former French tennis star and world number one, who won Wimbledon and the Australian Open women’s singles titles in 2006, was appointed as Murray’s coach last summer.
It is not known at this stage how Mauresmo’s news will affect, if at all, Murray’s schedule this season.
The baby, though, is due less than two months after Wimbledon, when Murray will bid to reclaim the crown he memorably won by beating Novak Djokovic in 2013.
Murray of course will have other things on his mind tomorrow as he marries Kim Sears in Dunblane.
Excitement in the town is building ahead of the event with crowds of well-wishers expected to line the streets.
The couple tie the knot at Dunblane Cathedral before a private reception at Murray’s £1.8million Cromlix House hotel. Guests are rumoured to include actor James Corden, television presenter Sue Barker and tennis player Tim Henman.