The fast bowler returns to the Test fold having last played in the longest format in August last year and joins fellow pacemen Kagiso Rabada, Marco Jansen and Dane Paterson in the 15-man squad.
The bowling unit is bolstered by all-rounders Wiaan Mulder and Corbin Bosch while the group features two frontline spinners in Keshav Maharaj and Senuran Muthusamy.
Temba Bavuma will captain the side and leads a strong batting contingent that includes Aiden Markram, Tony de Zorzi, Ryan Rickelton, Tristan Stubbs and David Bedingham while Kyle Verreynne is the wicketkeeper.
Proteas head coach Shukri Conrad said: "It is a special moment for this group to contest the WTC final. Over the past 18 months, we've worked hard to build a competitive red-ball unit, and this achievement reflects that progress.
"A key part of our success has been consistency in selection, and weâve stuck with the core group of players who have been part of this WTC cycle. We've selected a balanced squad for the conditions we expect at Lord's.
"I'm particularly pleased to welcome Lungi back in the side. He's put in the work and offers us an experienced option with the ball."
The Proteas squad will assemble in Arundel, Sussex on 31 May and will play a warm-up match against Zimbabwe from 3 June before heading to London on 7 June.
Proteas Test squad: Temba Bavuma (captain), David Bedingham, Corbin Bosch, Tony de Zorzi, Marco Jansen, Keshav Maharaj, Aiden Markram, Wiaan Mulder, Senuran Muthusamy, Lungi Ngidi, Dane Paterson, Kagiso Rabada, Ryan Rickelton, Tristan Stubbs and Kyle Verreynne