MUNICH, 27 Jun 2015 (AFP) -Morrison, 30, had been one shot off the lead on Friday but was in fine form on Saturday with a third-round 67 to reach 16 under par for the tournament.
Victory on Sunday would give the Englishman his second European Tour title in two months after he triumphed in the Spanish Open in May.
"I played good again," said Morrison, whose victory in Spain came five years after his maiden title in Madeira.
"I didn't really give anything away. The scoring has always been low over the years, so you have just got to keep going low and keep making birdies, and I did that."
Chris Paisley of England is second going into the final round with Thailand's Thongchai Jaidee a shot further back in third and Sweden's Peter Hanson fourth on 12 under.
Selected BMW International Open third round scores at the Munchen Eichenried Golf Club on Saturday (GBR/IRL unless stated, par 72):
200 - James Morrison 67 66 67
202 - Chris Paisley 69 67 66
203 - Thongchai Jaidee (THA) 68 67 68
204 - Peter Hanson (SWE) 69 68 67
205 - Carlos del Moral (ESP) 69 71 65, Michael Hoey 69 65 71, Pablo Larrazabal (ESP) 70 66 69
206 - Victor Dubuisson (FRA) 72 67 67, Kiradech Aphibarnrat (THA) 67 71 68, Rafael Cabrera Bello (ESP) 65 67 74
207 - Lasse Jensen (DEN) 65 69 73, Retief Goosen (RSA) 68 70 69, Ross Fisher 71 69 67, David Horsey 70 68 69, Gary Stal (FRA) 70 70 67, Tyrrell Hatton 71 70 66, Henrik Stenson (SWE) 67 71 69, Bradley Dredge 69 68 70
208 - Daniel Gaunt (AUS) 65 73 70, Thorbjorn Olesen (DEN) 71 68 69, Paul Lawrie 68 71 69, Shane Lowry 72 67 69, Kristoffer Broberg (SWE) 71 69 68, Alejandro Canizares (ESP) 70 66 72, Jaco Van Zyl (RSA) 70 68 70
209 - Lucas Bjerregaard (DEN) 71 67 71, Anthony Wall 70 69 70, Anders Hansen (DEN) 69 69 71, Garth Mulroy (RSA) 69 71 69, Pedro Oriol (ESP) 70 71 68, Marcel Schneider (GER) 68 70 71