Pete Walker (Patrick Niknejad) (1999-2005) and Frankie Perkins (Jordan Maxwell) (1999-2005), Josh's long-suffering friends. Pete has a pessimistic outlook on life and easily spots Josh's scams, but usually ends up getting drawn in anyway. Frankie's optimism is a foil for Pete's pessimism, but along with his dopeyness means he is often the target of Josh's scams. He has a long-held crush on Mel, and, in Series 7, he has a crush on Harry as well. Pete and Frankie have tried to desert Josh on several occasions, but always come back.

Wendy Richardson (Isabella Melling) (1999-2005), Lucy's only friend. In her scientifically-minded and studious nature she is very similar to Lucy, but as has been seen throughout the episodes, is not as smart and is even less in touch with popular culture than Lucy. Very pompous, and somewhat arrogant, she will always lose exams/tests to Lucy by 1%. Despite originally having strong feelings for Josh, she gets together with Frankie by the end of series seven.

Terence "Trent" Clements (Keith Warwick) (2000-2005), Mel's long-time friend. He endures Mel's mood swings with resignation and good humour, and it is hinted that he is romantically interested in her. They finally get together in Series 6.

Mr Graham Whiteside (Dan O'Brein) (1999-2005), Well known and very grumpy teacher. Particularly dislikes Josh Barker. Sophie has a bit of an obsession with him. He also has an obsession with Kate Winslet.

Mrs Alison Hardman (Beatrice Kelly) (1999-2005), One of Josh's teachers. Recurring character who dislikes Josh.

Poppy Manning (Kirsha Southward)(2002-2005), A girl who frequently appears as a rival to Josh, (and occasionally even the other Barkers), due to her similarly scheming, sneaky personality. She does, however in one episode really likes CJ

Tanya Thomas (Zoe Thorns)/(Emily Fleeshman)/(Sasha Tilley) (1999-2005), In the "Valentines Day" episode she has a secret affection for Josh Barker. Unfortunately, Josh mistakenly believes she has sent him hate mail and is determined to get back at her. Brian's well meaning attempts to ask her out while morphed as Josh apparently ruin any potential relationship. She gets together with her good friend, Pete Walker, in series seven..

CJ

CJ (Olisa Odele) (2004-2005): a small, quiet boy who was rescued from being run over by 'Superbrian', a.k.a. Brian Johnson wearing a cape. By strange coincidence he turns out also to be an orphan from the children's home and is adopted into the family because he finds out about Brian and Sophie being aliens and threatens to tell. CJ generally takes on the role of Brian's 'sidekick', and is therefore involved in many of Brian's ridiculous schemes and mad ideas. CJ has also been known to imitate Brian, although as the show progressed he became more independent. He is also sometimes the victim of jokes implying that (perhaps because of his age) he is less important or likable than the others, something he attempts to disprove such as when he offers himself as a slave for a day, and when he dates Poppy Manning.

Harry

Harriet 'Harry' (Stephanie Fearon) (2005): introduced at the start of series 7. Harry's real name is Harriet, but she snaps angrily at anyone who calls her that. Brian and Sophie adopted her when looking for a replacement for Mel, who had at the time left for Canada on an exchange trip. She is very similar to Mel in terms of personality, as she is usually moody and is a bit of a tomboy. She is also very protective of CJ because he is the youngest, although he finds her behaviour patronising. Like Josh, she plays the guitar, and her practising sometimes irritates the others.

Lucy Barker (Charlotte Francis) (1999-2005): Lucy Barker is the youngest and most intelligent Barker. At the start of the show she was nine years old. She is very talented in her school subjects, particularly in Maths and Science. Lucy's favourite subject is Chemistry. Lucy is very honest and moral. She easily sees through Mel and Josh's tough acts and voices their true feelings accurately. She is the most hard working sibling and their different personalities often clash. Lucy is well organised and studious, but sometimes lacks a sense of adventure. She can be quite uptight and slightly controlling. Despite these traits, she is the most kind and caring character. Lucy's above average intelligence means she often bonds with Brian (aliens have brilliant scientific knowledge but lack common sense). They usually play chess and conduct chemistry experiments. Lucy is often irritated by Brian's lack of sensitivity. She is very sensible and has a best friend named, Wendy Richardson. Wendy is equally intelligent and shares Lucy's goal to become an astronaut. Lucy and Wendy are not very popular, due to their scientific interests. Lucy's most prized possession is her chemistry set. Lucy also has a talent for judo. Like Josh, she wears braces in series 4