Ivan Perisic scored a 25th-minute winner to lift the Croatians above Norway after the Scandinavians conceded two second-half goals in a 2-1 defeat at group winners Italy, who also qualified.
The Italians finished on 24 points, four ahead of Croatia and five clear of Norway, with the latter confined to November's two-legged play-offs.
After learning that the result in Rome had turned their way, the Croatians endured a nervy last 10 minutes when they sat back on their slender lead.
Elsewhere in Group H, goals from Mihail Alexandrov and Dimitar Rangelov secured Bulgaria a 2-0 win Azerbaijan.
Two goals from midfielder Haris Medunjanin and a towering header from substitute Milan Djuric were enough to see Bosnia to a 3-2 victory in Cyprus to reach the playoffs of the Euro 2016 qualifying competition on Tuesday.
Bosnia and Herzegovina's Haris Medunjanin celebrates after scoring a goal during the Euro 2016 qualifying football match against Cyprus on October 13, 2015 in Nicosia
Image credit: AFP
Bosnia finished third in Group B behind Belgium and Wales, edging Israel and Cyprus in the race for a place in Sunday's play-off draw.
It was a hard fought victory for Mehmed Bazdarevic's men, who had to come back from 2-1 down late in the first half without talisman Edin Dzeko.
Belgium secured top spot in Group B after Dries Mertens made up for a howling first-half miss to score and set up another in their 3-1 Euro 2016 qualifying victory over Israel.
Belgium's forward Dries Mertens celebrates after scoring during the Euro 2016 qualifying football match between Belgium and Israel at the King Baudouin Stadium in Brussels on October 13, 2015
Image credit: AFP
The win means Belgium are also set to rise to number one in FIFA's volatile ranking system, while Israel's hopes of reaching the tournament in France next year were ended.
Wales ended their successful Euro 2016 qualifying campaign with a 2-0 win over a surprisingly resilient Andorra in their final Group B match at the Cardiff City Stadium on Tuesday.
Wales's midfielder Gareth Bale (centre R) and Wales's midfielder Aaron Ramsey (3R) celebrate with teammates following the Euro 2016 qualifying football match between Wales and Andorra at Cardiff City stadium in Cardiff, south Wales, on October 13, 2015
Image credit: AFP
Goals from Aaron Ramsey after 50 minutes and Gareth Bale in the 86th, sealed their sixth win of the campaign which has ended with them reaching a major tournament for the first time since the 1958 World Cup finals.
The Netherlands' hopes of a dramatic rescue act in Euro 2016 qualification evaporated as they conceded two first-half goals and eventually lost 3-2 at home to 10-man Czech Republic on Tuesday.
Netherlands' Wesley Sneijder reacts at the end of the Euro 2016 qualifying fooball match Netherlands vs Czech Republic at the Amsterdam Arena in Amsterdam, October 13, 2015.
Image credit: AFP
The Dutch, third at the World Cup in Brazil last year, had to win their final qualifier and hope Turkey lost at home to Iceland to sneak into third place in Group A and book a slot in next month's playoffs.
However, defeat consigned the Netherlands to fourth spot behind the Turks, who won 1-0 to secure a place at the finals as the best third-placed team, while the Czechs topped the group.
After Kazakhstan also overcame Latvia 1-0 it meant Turkey had a better record against the other top five teams in their group, compared with Hungary in Group F, who finished their campaign on Sunday.
STATE OF PLAY ON ROAD TO EURO 2016 FINALS
Qualified:
Group A: Iceland, Czech Republic
Group E: England, Switzerland
Group F: Northern Ireland, Romania
Group I: Portugal, Albania
Best 3rd team: Turkey (Group A)
The remaining four finalists will be decided after the two-legged play- offs being held between November 12-17.
Eight teams to play-offs:
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