West Ham reached their first European final for 47 years after Thursday's 1-0 victory at AZ Alkmaar clinched a 3-1 aggregate success in the Europa Conference League semi-finals.
Pablo Fornals scored West Ham's winner in the final moments of the tense second leg to set up a clash with Fiorentina or FC Basel in the final in Prague on June 7.
The Hammers last reached a major European final in 1976 when they were beaten by Anderlecht in the Cup Winners Cup.
West Ham have not won a major trophy since Trevor Brooking's goal beat Arsenal in the 1980 FA Cup final.
They lost the 'Steven Gerrard' FA Cup final on penalties after a 3-3 draw against Liverpool in 2006.
Last season, West Ham lost 3-1 on aggregate to eventual winners Eintracht Frankfurt in the Europa League semi-finals.
David Moyes' side have made amends for that painful near-miss by reaching the final of a competition much-maligned in some quarters, but never again in east London.
West Ham have won 13 of their 14 games in the competition this season and will be favourites whoever they play in the final.
Moyes has led West Ham to top 10 finishes in the Premier League in the past two seasons, but they have struggled for much of the current campaign.
They are 15th in the table with two games left, all but mathematically safe from relegation.
Winning a European trophy would be an unexpectedly uplifting end to their troubled season.
However, their victory over AZ was tarnished slightly after fans from both clubs were involved in fighting after the final whistle.
A group of Alkmaar fans appeared to get into the section holding West Ham's 700 away supporters, prompting ugly scenes before police and stewards quelled the violence.