In modern Sweden, Midsummer's Eve and Midsummer's Day (Midsommarafton and Midsommardagen) were formerly celebrated on June 23th and 24th, but since the 1950's on the Friday between June 19th and June 25th and the following Saturday. It is arguably the most important holiday of the year, and one of the most uniquely Swedish in the way it is celebrated, even if it has been influenced by other countries long ago.

The main celebrations take place on the Friday, and the traditional events include raising and dancing around a huge maypole. One typical dance is the frog dance. Before the maypole is raised, greens and flowers are collected and used to cover the entire pole.

Raising and dancing around a maypole is an activity that attracts families and many others. People dancing around the pole listen to traditional music and many wear traditional folk costumes. The year's first potatoes, pickle herring, sour cream, and possibly the first strawberries of the season are on the menu. Drinking songs are also important at this feast, and many drink heavily.

Because Midsummer was thought to be one of the times of the year when magic was strongest, it was considered a good night to perform rituals to look into the future. Traditionally, young people pick bouquets of seven or nine different flowers and put them under their pillow in the hope of dreaming about their future spouse. In the past it was believed that herbs picked at Midsummer were highly potent, and water from springs could bring good health. Greenery placed over houses and barns were supposed to bring good fortune and health to people and livestock; this old tradition of decorating with greens continues, even though most don't take it seriously.

To decorate with greens was called att maja (to may) and may be the origin of the word majstång, maja coming originally from the month May. Other researchers say the term came from German merchants who raised the maypole in June because the Swedish climate made it impossible to find the necessary greens and flowers in May, and continued to call it a maypole. Today, however, it is most commonly called a midsommarstång.

In earlier times, small spires wrapped in greens were erected; this probably predates the maypole tradition, which is believed by many to have come from the continent in the Middle Ages.
Others argue that some form of Midsummer pole occurred in Sweden during the pre-Christian times, and was a phallic fertility symbol, meant to impregnate the earth, but as there were no records from those times it cannot be proven, and this idea might just be a modern interpretation of the poles form. The earliest historical mention of the maypole in Sweden is from the Middle Ages.

Midsummer was, however, linked to an ancient fertility festival which was adapted into St. John's Day by the church, even though it retained many pagan traditions, as the Swedes were slow to give up the old heathen customs. The connection to fertility is naturally linked to the time of year. Many young people became passionate at Midsummer, and this was accepted, probably because it resulted in more childbirths in March which was a good time for children to be born.