“Sirius” Genealogy: The Complex Harry Potter Family Tree

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Family bonds form an important part of the beloved Harry Potter series. And with so-called “blood purity” a recurring element in the series, genealogy places itself at the forefront of book-lovers’ favorite Wizarding World. As a result, the Harry Potter family tree plays an important role in the series, and it’s ripe with genealogical questions to explore.

Let’s take a look at the Harry Potter family tree and learn how the major characters in the Harry Potter universe are related.

Harry-tage: The Potter Family Tree

Our hero, Harry Potter, is the son of James Potter (the last heir of a famous medieval wizarding family) and Lily Evans (a Muggle-born witch). An orphan from a young age, Harry was raised by his only living blood relatives: his non-magical maternal aunt, Petunia Dursley (née Evans), and her husband, Vernon.

Though Harry hated living with the Dursleys, ancient magic protected him so long as he lived under the Dursleys’ roof. Harry also has a first cousin, the portly Dudley Dursley.

famous family trees, fictional family trees, Harry Potter genealogy — This family tree, a mock up in Ancestry.com, shows the known ancestors and relatives of Harry Potter—including information added by J.K. Rowling after the books’ release.

Though we don’t learn much about older generations of Harry’s family throughout the series, J.K. Rowling detailed the history of the Potter family online. Harry found himself the sole descendant of the Potters, a lineage that stretches back to a 12th-century potion-maker named Linfred of Stitchcombe. Rowling also discusses Harry’s paternal grandparents (Fleamont and Euphemia Potter) and his great-grandfather (Henry “Harry” Potter, Harry’s potential namesake).

Notably, Rowling’s article dispelled the fan theory that James was the son of Charlus Potter, a man who married into the Black family. This would have made Harry third or fourth cousins with many characters (including his future wife, Ginny Weasley). Even so, Charlus Potter might relate to Harry’s Potter line, albeit more distantly than fans originally thought.

Black Sheep Ancestors: The Black Family Tree

Speaking of the Black family: Perhaps the more interesting portion of the “Harry Potter” family tree doesn’t even feature Harry. In Harry Potter and the Order of the Phoenix, we learn about the genealogy of Sirius Black, Harry’s godfather.

Sirius’ great-great-grandfather, Phineas Nigellus Black, has among his descendants many of the series’ most important characters. Phineas and his wife, Ursula Flint, had five children, three of whom gave rise to important Harry Potter characters. We can mostly easily see this in the image below, hand-drawn by J.K. Rowling for a charity auction.

Sirius is the son of Orion and Walburga Black, great-grandchildren of Phineas Nigellus Black (and themselves second cousins). Ashamed of his Dark-leaning relatives, Sirius had a complicated relationship with his family and ran away from home at 16. Indeed, his mother blasted him (and other “traitors”) off the family tree that hung in the ancestral Black home.

Sirius had good reason to avoid his relatives, as many in his family served as Death Eaters. His brother, Regulus, joined the Death Eaters at a young age (and, to his credit, died for defecting from their cause). Most notably, his first cousin Bellatrix Lestrange (née Black) considered herself Voldemort’s most loyal servant. Her sister Narcissa (another of Sirius’ first cousins) married Lucius Malfoy, himself a renowned Dark wizard instrumental to Voldemort’s rise. Harry also fought against their son (Sirius’ first cousin once removed), Draco, a wannabe Death Eater tasked with killing Albus Dumbledore.

Confused yet? Try not to look too closely, as the Black tree gets even messier because of intermarriage. For example, Bellatrix and Narcissa, in addition to being Sirius’ first cousins, are also his third cousins on his mother’s side.

Red-headed Stepchildren: The Weasley Family Tree

Harry’s adopted family, the Weasleys, also belong to the “Most Ancient and Noble House of Black,” albeit in name only. Arthur Weasley is the son of Cedrella Black (a granddaughter of Phineas Nigellus Black) and Septimus Weasley. Septimus, a “Muggle-loving” wizard, brought dishonor to the pure-blooded Black family. And so, the Blacks blasted Cedrella (like Sirius) from the tree for her treachery.

So how are Sirius and the Weasleys related? Phineas Nigellus Black is Sirius’ great-great-grandfather and Arthur’s great-grandfather, making the two men second cousins once removed. (Sirius correctly notes the relationship in Order of the Phoenix.) Given that, Sirius can call the seven Weasley children his third cousins. And though Sirius didn’t live to meet him, Harry and Ginny Weasley’s son James Sirius is his third cousin once removed.

A Family Affair

Given all these connections, you could describe many of the series’ conflicts as family reunions gone wrong. In Order of the Phoenix, Bellatrix kills her first cousin Sirius, only to later be killed by Molly Weasley (Bellatrix’s second cousin once removed by marriage).

In addition, Lucius Malfoy and Arthur Weasley have a well-established feud despite being second cousins once removed by marriage. Lucius even tries to kill Ginny Weasley, his third cousin by marriage, in Chamber of Secrets. And when Draco sneers at Ron Weasley’s “red hair, hand-me-down robes and stupid complexion,” he might not realize he’s actually insulting his third cousin once removed.

Have other fictional family trees you want us to explore? Stay tuned for more deep dives into fictional ancestries, and check out our cousin calculator to perform your own.