In Doppelgängland, Faith says about Wesley, “Princess Margaret here had a little trouble keeping up.” Princess Margaret was the younger sister of Queen Elizabeth II. She was born in 1930 and died in 2002, after bad health problems including a stroke, a heart attack, and lung surgery.

Buffy was the nickname of Queen Elizabeth II’s mother, also named Elizabeth. The “Queen Mother” as she was known, died in March 2002. Buffy is a common nickname for those with the full name Elizabeth.

“Buffy” is also the name of a gene, first isolated in Drosophila (fruit flies), and its corresponding protein. What the protein does is save the cell if it’s been instructed to die.

When he’s playing Dungeons and Dragons in Chosen, it looks like the red cape that Andrew is wearing was the one Buffy wore when she dressed as Little Red Riding Hood in Fear, Itself.

At the end of When She Was Bad, when Buffy is chatting with Giles before she goes to class, she is wearing a gold inverted cross necklace. An inverted cross or crucifix is typically a sign of an allegiance to evil, so it is odd to see it on a …

In Killed by Death, Xander says, “Buffy, this is not the time to challenge Angel for the ultimate fighting championship.” The Ultimate Fighting Championship, or UFC, is a competition in America where fighters compete using martial arts inside of an Octogon instead of a normal boxing ring. When it first …

In the episode Grave, Willow says “Willow doesn’t live here anymore”. This is probably a reference to Martin Scorsese’s movie Alice Doesn’t Live Here Anymore (1974). The movie is about a recently widowed woman who decides to pursue a more glamourous lifestyle.

The tweed suit Spike wears for most of the episode Tabula Rasa is similar to the one he wore in Xander’s dream in Restless. It was in this dream that Giles said he looked upon Spike as a son. As they both have English accents, they assume they are related …

In All the Way, Willow uses Lethe’s Bramble to perform a forgetting spell on Tara (and herself and her friends, by accident, in Tabula Rasa). Tara discovered what Willow had done in Once More, With Feeling when she researched Lethe’s Bramble in a book at the Magic Box. It said: …

Xander wears an eye patch when he is dressed as a pirate in All the Way. Xander’s eye was removed by Caleb in season seven’s Dirty Girls and he then had to wear an eye patch. He even references the costume when he’s in hospital in Empty Places: “Well, to …

In All the Way, Xander says, “Store. Go boom.” In Shadow, Willow said, “Tomb. Go boom” after Riley blew up a tomb in the graveyard.

Both Dawn and Janice tell their families in Life Serial that they are staying at each others’ houses. Buffy should have checked with Janice’s mother as she and her friends did this in Surprise when researching the Judge.

For Halloween in All the Way, Xander dresses as a pirate, Anya as a Charlie’s Angel and Giles as a wizard. Other costumes seen include: a fireman; a bee; the Queen of Hearts; three witches; a demon; a prisoner; Princess Leia and Luke Skywalker; a milkmaid; a gorilla; Flash Gordon; …

We finally discover in All the Way why Giles spends a lot of his time cleaning his glasses: Buffy realises, “Is that why you’re always taking off your glasses? So you don’t have to watch what we’re doing?” to which Giles replies “Tell no one.”

In All the Way, Xander gives children sweets at the Magic Box. He says, “These be fireflies spat from a volcano off the coast of Katmandu.” This may be a nod towards Joss Whedon’s TV show Firefly.