The short answer is July 2017, which is when the women’s team reached Euro 2017, finishing third in Group D behind England and Spain and ahead of Portugal on goal difference.
The men’s European Championship has been on the go since 1960 but Scotland have qualified just twice ahead of the current edition.
Scotland's maiden appearance at the European Championship came in 1992, in Sweden. Before this they had managed a collection of third- and fourth-place finishes in qualifying.
In the convoluted qualifying process for Euro 1968, Scotland finished a point behind England in the group stages – which was based on British Home Championship results – meaning they missed out on an appearance in the final qualifying stage before the tournament proper.
The Scots finished top of Euro 92 Qualifying Group 2 ahead of Switzerland, Romania, Bulgaria, and San Marino with 11 points from eight games.
In the final tournament Scotland were grouped with Germany, the Netherlands, and the Commonwealth of Independent States (CIS), the transitional national team of the Football Federation of the Soviet Union in 1992.
A narrow 1-0 defeat by the Netherlands and a 2-0 loss to Germany meant the 3-0 win over the CIS was largely immaterial, and Scotland returned home.
The Netherlands were knocked out by Denmark in the semi-finals on penalties, with the Danes going on to beat Germany in the final after the Germans had seen off hosts Sweden in the other last-four tie.
Scotland were drawn in Group 8 with the Faroe Islands, Finland, Greece, Russia, and San Marino. They won seven, drew two, and lost just one of their ten matches, recording home and away wins against the Faroes, the Finns, and San Marino as well as a home win against Greece, two draws with Russia, and defeat in Athens.
Their 23 points sealed qualification to Euro 96 as one of the best-performing group runners-up. Scotland qualified as the fourth-best runner-up behind Italy, Bulgaria, and Turkey and ahead of Denmark and France. The Republic of Ireland and the Netherlands faced off in a one-game play-off to determine the last nation to qualify with the Dutch winning 2-0.
Scott Booth and John Collins were Scotland’s top scorers during qualifying with four goals each with Ally McCoist, John McGinlay, and Billy McKinlay netting two apiece.
Scotland were drawn in Group A along with hosts England, qualifying Group 3 winners Switzerland, and their old Euro 92 nemesis the Netherlands. It was the first time the Swiss had featured at a European Championship but England had finished third in Euro 1968 and the Netherlands had won the competition in 1988.
England and Switzerland drew the opening game at Wembley 1-1, Alan Shearer’s 29th minute opener cancelled out by Kubilay Turkyilmaz’s late penalty.
Two days later, Scotland played the Netherlands at Villa Park and did well to hold the Dutch to a goalless draw.
The Dutch then defeated Switzerland 2-0 at the same venue, before Scotland went down 2-0 to England at Wembley in a match famous for David Seaman’s penalty save from Gary McAllister, and Paul Gascoigne’s superb solo goal and controversial celebration.
In the final round of fixtures, Scotland knew that victory against the Swiss and a win for England against the Netherlands by four goals or more would take them into the quarter-finals.
McCoist opened the scoring in the 36th minute after spurning two presentable chances but with Craig Brown’s side a goal up, news filtered through that England were four goals to the good against the Dutch thanks to braces from Shearer and Teddy Sheringham.
With time running out in both matches, things looked good for Scotland until Patrick Kluivert struck 12 minutes from time at Wembley to send the Dutch through on goal difference.
Had Scotland scored twice against Switzerland at Villa Park they would have advanced to play France in the knockout stages. The French beat the Netherlands on penalties before being knocked out via penalty shoot-out against Scotland’s Euro 2020 group opponents Czech Republic.
1996 – 2020
Scotland reached the Euro 2000 and Euro 2004 play-offs, losing to 2-1 on aggregate to England in November 1999 and 6-1 on aggregate to the Netherlands in November 2003.
On both occasions, Scotland won one of the legs 1-0.
In qualifying for Euro 2008, Scotland finished third in their qualifying group. Despite beating France at home and away, a controversial late defeat to Italy and a shocking 2-0 reversal in Georgia consigned Scotland to third, just two points behind runners-up France.
In Euro 2012 qualifying Scotland again finished third, two points behind the runners-up. A goalless draw with Lithuania in Kaunas and losing a late goal to draw against the Czechs at Hampden put paid to Scotland’s chances.
Ahead of Euro 2016 Scotland finished fourth, missing out on the play-offs by three points. Another defeat in Georgia coupled with some fine results for the Republic of Ireland against Germany – a win in Dublin and a late, late point in Gelsenkirchen – didn’t help Scotland’s cause; neither did losing another late goal at Hampden to snatch a draw from the jaws of victory, this time against Poland.
In this summer's finals, Scotland will again meet neighbours England, as well as Croatia and Czech Republic.
Second place would guarantee a place in the knock-out stages but even finishing third might be enough depending on ranking.
If they finish second they will face Spain, Sweden, Poland, or Slovakia – whichever team finishes runners-up in Group E.