Petersson is a Swedish patronymic name meaning “Peter's son.” It did not begin as the name of one clan. Under Sweden's older naming system, unrelated sons of unrelated men called Peter could each be known as Petersson. Today it is normally an inherited surname, so a present-day Petersson need not have a father named Peter.
How the Name Is Formed
The construction is Peter + the possessive or relationship-marking s + son: in plain English, “Peter's son.” The two consecutive s's in Petersson belong at the join between Peters and son; the name is not Peter plus a special ending -sson with a separate meaning.
The deeper “rock” meaning belongs to the personal name Peter, not to the surname's original social function. The University of Oxford's Lexicon of Greek Personal Names gives Greek Petros as “rock” and connects its adoption as a personal name with the New Testament apostle. For Swedish, Eva Brylla's name-dictionary entry published by the Institute for Language and Folklore (Isof) describes Peter as a Nordic form of Petrus. It records the Old Swedish spellings Pætar and Pæter, dates Swedish evidence for the name to the later fourteenth century, and notes that the present form was later borrowed again from German.
Thus “son of Peter” is the historically useful surname meaning. “Son of the rock” is an etymological paraphrase one stage further back, not a literal description of how a Swedish bearer acquired the name.
From Patronymic to Hereditary Surname
A patronymic identifies someone through a parent's given name. Isof's explanation of Swedish patronymics gives the regular historical pattern: a father's name was followed by -son for a son or -dotter for a daughter. In a family headed by a Peter, a son might therefore be Lars Petersson and a daughter Karin Petersdotter. If Lars later had a son, that child would ordinarily receive a patronymic based on Lars rather than inherit Petersson.
This distinction matters when reading Swedish records. Isof's history of surnames in Sweden says that patronymics remained especially persistent among rural and lower-status groups. They changed from one generation to the next until many -son forms began to be passed down as family surnames in the late nineteenth century. The transition was not simultaneous everywhere, and hereditary -son names also existed earlier.
By around 1900, many men retained their existing patronymic as a fixed surname. Women generally did not turn -dotter patronymics into hereditary family names: Isof notes that women could instead take their father's patronymic as a surname or replace the -dotter ending of their own patronymic with -son. Sweden's first surname ordinance followed in 1901, while general use of fixed surnames belongs mainly to the early twentieth century. Consequently, Petersson can be a literal father-name in one record set and an inherited family surname in another.
Peter, Petter, Per, and the Similar Surnames
Petersson, Pettersson, and Persson preserve different written bases—Peter, Petter, and Per—but those given names are historically related. The Swedish National Archives' guide to personal and family research groups Per with Peder, Pehr, Petrus, Peter, Petter, and Pär as alternative name forms that may appear for the same person. It also cautions that the parish priest controlled the form entered in older population records.
That evidence calls for two kinds of care:
- Do not treat the variants as unrelated etymologies. They belong to the same broad Peter/Petrus name family.
- Do not merge their records automatically. Petersson, Pettersson, and Persson are distinct modern surname spellings, and two people with similar names in one parish may still be different individuals.
Petersdotter is different again: in historical Swedish material it is the corresponding daughter patronymic, not merely a casual spelling of Petersson. It may identify a sister of a Petersson while the active patronymic system is in use, but it is not proof of that relationship without the underlying household or birth record.
Petersson in Sweden Today
Petersson remains a major Swedish surname. Skatteverket's official 2026 list of common surnames records 24,871 people named Petersson. In the same list, Pettersson has 54,579 bearers and Persson 90,597. These totals are for the exact registered forms: Skatteverket's name-search guidance explicitly says that alternative spellings are not combined.
The figures show both the importance of the wider Swedish -son tradition and the continuing separation of the spellings. They do not measure one Petersson lineage, and they cannot show whether two bearers are related.
Petersson and Peterson
Peterson can be connected with Petersson, particularly where a Swedish name was adapted to a spelling with one s. Patrick Hanks's Dictionary of American Family Names treats Peterson as an Americanized form—and also a less common Swedish variant—of Petersson. The same dictionary also identifies independent English, Scottish, and German patronymic origins for Peterson.
For that reason, Peterson is a plausible documentary variant but not an automatic equivalent. A change from Petersson to Peterson should be demonstrated in records belonging to the same person or family. Conversely, the spelling Peterson alone does not establish Swedish ancestry.
What the Surname Can and Cannot Show
The surname can indicate a Swedish naming tradition and, in an older patronymic context, may point directly to a father recorded as Peter or under a related form. Once the name became hereditary, that inference no longer follows: the surname could pass unchanged even when no recent father was named Peter.
Because the patronymic was formed repeatedly, shared spelling is not evidence that all Peterssons descend from one founder. The reliable genealogical question is not “Which original Petersson family did this person belong to?” but whether the records for a particular place and period use Petersson as a changing patronymic, an additional name, or a fixed surname.
References
- Eva Brylla, “Peter”, in Förnamn i Sverige: kortfattat namnlexikon, Liber, 2004; web version updated by the Institute for Language and Folklore, 2023.
- Institute for Language and Folklore (Isof), “Efternamn” (Surnames), overview of Swedish surname history and patronymics.
- Institute for Language and Folklore (Isof), “Vad är ett patronymikon?” (What is a patronymic?), published 2021.
- Riksarkivet (Swedish National Archives), “Om släkt- och personforskning” (About family and personal research), guidance on Swedish patronymics and historical given-name forms.
- Skatteverket (Swedish Tax Agency), *Fria efternamn 2026, sorterade i antalsordning*, official 2026 bearer counts, with name-search methodology.
- University of Oxford, Lexicon of Greek Personal Names, “Greek Names in English”, entry for Peter/Petros.
- Patrick Hanks, ed., Dictionary of American Family Names, Oxford University Press, 2003, “Peterson” entry reproduced by FamilySearch.