The Swedish alphabet is a basic element of the Latin writing system used for the Swedish language. The 29 letters of this alphabet are the modern 26-letter basic Latin alphabet (A through Z) plus Å, Ä, and Ö, in that order.
The Swedish alphabet has 20 consonants: b, c, d, f, g, h, j, k, l, m, n, p, q, r, s, t, v, w, x, z, and 9 vowels: a, e, i, o, u, y, å, ä, ö.
The letter Q is rare. Q was common in ordinary words before 1889, when its replacement by K was allowed. The letter W is rare as well. Before the 19th century, W was interchangeable with V. The letter Z is also rare, used in names and a few loanwords such as zon (zone).
The letters å, ä, ö are not variations of a and o or umlauts, like in German. They are fully independent letters in the Swedish alphabet that are just written this way.
There are a few letters that you can see in some Swedish words and names but they are not part of the alphabet. Though not in the official alphabet, á is a Swedish (old-fashioned) letter. In native Swedish personal names, ü and è and others are also used. For foreign names, ç, ë, í, õ, and many others might be used, but are usually converted to c, e, i, o, etc.
The Latin alphabet was brought to Sweden along with the massive Christianization of the population. Swedish first appeared in the Latin alphabet in 1225 in the Westrogothic law, the code of law used in the province of West Gothland. The language of this text is known as Early Old Swedish, which was used until about 1375. It was grammatically much more complex than modern Swedish.
The translation of the Bible into Swedish in 1526 is seen as marking the beginning of modern Swedish. It helped to establish a consistent orthography for Swedish, although the spelling used in the translation was not completely consistent.
Modern Swedish spelling rules were created by the author Carl Gustaf Leopold, who was commissioned to do so by the Swedish Academy. The spelling was reformed in 1906, and that reform was only fully supported by the Swedish Academy in 1950.
Runes continued to be used in Sweden throughout the first centuries of Christianity, even for ecclesiastic purposes, despite their traditional relation to Nordic paganism. The runes underwent partial “latinization” in the Middle Ages, when the Latin alphabet was completely accepted as the Swedish script system, but runes still occurred, especially in the countryside, until the 18th century, and were used decoratively until mid 19th century.