Fifth seed Sharapova, the 2004 champion, and now the overwhelming favourite for the title following the fourth round defeats of Serena and Venus Williams, brushed aside Slovakia's Dominika Cibulkova 6-1, 6-1 in her quarter-final.
Lisicki, the first German woman to make the semi-finals since Steffi Graf in 1999, and only the second wildcard to reach the last four, saw off French ninth seed Marion Bartoli 6-4, 6-7 (4-7), 6-1.
Cibulkova, who had stunned world number one and top seed Caroline Wozniacki in the last 16, never looked like repeating that upset against Sharapova.
"It's an honour to be in the semi-final. It's a few years since I've got past the fourth round so it's a great chance to take it a step further," said Sharapova, who believes she has got stronger as the tournament has progressed.
"I certainly feel like I've improved, especially from my second round. I think that's really important if you want to get to the later stages," she said.
"You have to step it up because the matches will only get tougher and you're going to be playing better players."
Lisicki, whose career went into a tailspin when an ankle injury left her barely able to walk, is determined to capitalise on her shock run, just in case it's her last opportunity.
The 21-year-old recovered from wasting three match points in the second set to defeat Bartoli, the 2007 runner-up, who had defeated four-time winner Serena Williams in the fourth round.
Lisicki had already been a quarter-finalist in 2009 before disaster struck in 2010 when an ankle injury picked up in Miami sidelined her for five months and sent her ranking plummeting to 218.
"I'm more experienced and calmer. Two years ago it was different. I was more nervous. I couldn't sleep so good," said the German.
"But now it's different. After the injury, I know how fast it can be gone. I just try to enjoy every minute that I'm on the court."
Lisicki fired 52 winners past Bartoli and hit the 121mph serving mark just as she had done when she knocked out China's French Open winner Li Na in the second round.
Thursday's other semi-final will see Czech eighth seed Petra Kvitova face Belarus's Victoria Azarenka.
Fourth seed Azarenka buried her grand slam quarter-final jinx to reach her first Wimbledon semi, defeating Austria's Tamira Paszek in a match played on two different courts.
Azarenka had lost all of her previous four quarter-finals at the majors, but the 21-year-old shook off that record to win 6-3, 6-1 against her unseeded opponent.
She dedicated the win to her mother who was celebrating her birthday on Tuesday.
"I wanted to give her a good gift, I wanted to play beautifully," said Azarenka, who has lost her last two matches to Kvitova - here in the third round in 2010 and in May's Madrid Masters final on clay.
"Petra is a great player. The grass suits her, she has a huge serve. I will have to play my best tennis."
The match had started on Court One but after Paszek had won the first game, the contest was suspended at 1820 GMT because of the slippery conditions caused by the heavy rain which had disrupted the day's schedule.
One hour later, the two players resumed the contest but this time under the roof of Centre Court.
Kvitova secured a second successive semi-final spot with a 6-3, 6-7 (5-7), 6-2 win over Bulgaria's Tsvetana Pironkova.
Kvitova, who could become the first left-hander to win the women's title since Martina Navratilova in 1990, had dropped just 15 games in her first four matches.
Pironkova, a semi-finalist last year and who put out five-time champion Venus Williams on Monday, pushed Kvitova but the 32nd seed was out-muscled.
"I am so happy to be in the semi-final. I made some mistakes in the second set and was a bit down mentally," said Kvitova.
"It's great to be back in the semi-final and now I have more experience of the Centre Court."
Jana Novotna was the last Czech woman to lift the Venus Rosewater Dish awarded to the women's champion back in 1998.
- AFPTags: sport, tennis, england First posted June 29, 2011 05:56:00