Thiem became the first Austrian since Thomas Muster in 1996 to reach the final of the claycourt tournament after subduing Murray for the first time in his career.
Rafael Nadal reached the final of the Barcelona Open by dispatching Argentine Horacio Zeballos 6-3, 6-4 on Saturday to book his place in Sunday's showpiece against Dominic Thiem where he will be looking to win the tournament for a 10th time.
Nadal struck the first blow by breaking the unseeded Zeballos in the fourth game and the difference in quality between the two players soon began to show.
Zeballos earned two break points in the fourth game of the second set but 14-time grand-slam winner Nadal recovered to hold his serve and wrapped up his victory in 94 minutes, setting up a re-match with Thiem, who beat him last year on clay in the Argentina Open semi-finals.
World No 1 Andy Murray was knocked out 6-2, 3-6, 6-4 by Austria's Dominic Thiem in the semi-finals of the Barcelona Open on Saturday.
Thiem became the first Austrian since Thomas Muster in 1996 to reach the final of the claycourt tournament after subduing Murray for the first time in his career.
Just as in Friday's gruelling quarter-final with Albert Ramos-Vinolas, Murray got off to a bad start.
The Briton relied on his serve to recover the second set but could not sustain the level and bowed out.
Thiem will meet either nine-times Barcelona Open champion Rafael Nadal or Argentine Horacio Zeballos in Sunday's final.