Galway claimed a deserved 0-16 to 0-11 success in the Connacht Senior Football Championship semi-final at Markievicz Park.
With Tom Flynn and Fiontan O'Curraoin effective at centrefield, Galway shaded an interesting first half to go in 0-09 to 0-08 ahead.
In the second period Shane Walsh was immense for Galway, who pulled five points clear in the third quarter.
Late on Sligo needed a goal, but the Galway defence was never in any serious danger as Alan Mulholland's side held on.
Early on there was plenty to admire in the manner Galway moved the ball quickly with promising centre forward Walsh impressive.
The former St Jarlath's College star was busy scoring and creating chances for an inside line in which Danny Cummins was craving involvement.
Twelve minutes in, the teams were deadlocked at 0-03 each following plenty of early industry from both outfits.
An Adrian Marren free edged Sligo ahead, but then Galway reeled off three nice points on the spin courtesy of Michael Martin (two) and Walsh.
From then until the break it remained keenly contested as a Shane McManus score kept Sligo very much in the reckoning during a burst of Galway pressure.
O'Curraoin and Flynn were productive in the middle for Galway, who went 0-09 to 0-05 in front by the 34th minute with Walsh continued to cause problems.
But two scores in the closing seconds of the half from Mark Breheny and Marren ensured only the narrowest of margins divided the teams at half-time.
Ten minutes after the break Flynn released Cummins, who forced a brilliant reaction save from Sligo custodian Aidan Devaney.
Walsh assumed responsibility, knocking over the resultant '45 which put Galway 0-11 to 0-09 ahead clear in the 46th minute.
Sligo were being put under pressure and two further points from the splendid Walsh and one from Cummins extended Galway's advantage.
Sligo terminated an 11-minute search for a score when substitute Kevin McDonnell clipped a point, but Galway replied instantly through Damien Comer.
Late on Niall Murphy and Walsh traded points as Galway closed out the deal to book a provincial decider date with Mayo on July 13.
Galway: M Breathnach; D O’Neill, F Hanley, A Tierney; G Bradshaw, G O’Donnell, P Varley; F O’Curraoin, T Flynn; M Lundy (0-01), S Walsh (0-06, 2fs, 145), D Comer (0-01); M Martin (0-02, 1f), E Hoare (0-02), D Cummins (0-04).
Subs: P Conroy for Hoare (54 mins), A Varley for Martin (60 mins), S Armstrong for Cummins (61 mins), J O’Brien for Comer (65 mins), C Mulryan for Lundy (70 mins).
Sligo: A Devaney; R Donovan, J Martyn, N Ewing; C Harrison, A McIntyre, K Cawley; J Kilcullen, S McManus (0-01); D Rooney, M Breheny (0-02), B Egan; P Hughes (0-01), A Marren (0-04, 1sideline, 1 free), D Kelly (0-01).
Subs: B Curran for Harrison (39 mins), K McDonnell (0-01) for McManus (51 mins), N Murphy (0-01) for Rooney (55 mins), S Coen for Hughes (55 mins), G Ryan for Martyn (63 mins), E McHugh for Breheny (65 mins).
Referee: M Deegan (Laois).