!!Present Across the Series
* HeyItsThatGuy:
** BrianBlessed throughout season 1.
** [[Series/{{House}} Doctor House]] is George in seasons 3 and 4.
** In Blackadder II, he also appears as one of Blackadder's friends in "Beer" and is the BigBad as Prince Ludwig in "Chains".
** On that note, Series/MrBean (or, if you like, JohnnyEnglish) is the title character.
** And Baldrick is that bloke from ''TimeTeam''.
** And there's also that really clever guy from ''{{QI}}'' as the Melchetts and the {{Duke of Wellington}}.
** Actually, most Brits would probably recognise Stephen Fry (Melchett) and Hugh Laurie (George) from ''ABitOfFryAndLaurie''. Or ''Series/JeevesAndWooster''.
** [[Film/HarryPotter Rita Skeeter]] as the Queen, the highwaywoman and the nurse (from ''Goes Forth'').
** The [[TomBaker Fourth Doctor]] shows up as a drunken sea captain. ''Arrrr...''
** And [[Film/HarryPotter Horace Slughorn]] as the Spanish Interpreter in the first seasons 'Queen of Spain's Beard'.
*** Or, [[HotFuzz Chief Inspector Butterman]] is Prince Albert.
** And [[Film/HarryPotter Professor Sprout]] as an Infanta of Spain in series 1, Blackadder's aunt in series 2 and Queen Victoria in ''Blackadder's Christmas Carol.''
** Three of ''Series/TheYoungOnes'' have also guest starred on the show - Rik (Rik Mayall) as Mad Gerald in series 1 and Flashheart in series 2 and 4, Neil (Nigel Planer) as Smedley, the Scarlet Pimpernel's associate in series 3, and Vyvyan (Adrian Edmondson) as the Red Baron in series 4.
** [[Series/RedDwarf Arnold Rimmer]] as the French prison guard in ''Blackadder the Third''.
** [[Film/HarryPotter Hagrid]] plays Dr. Samuel Johnson, inventor of the Dictionary, in series 3. He's also the ghost of Christmas in ''Blackadder's Christmas Carol''.
** Ebenezer Blackadder's niece, Millicent, is [[Series/DoctorWho Peri]].
** [[Film/RaidersOfTheLostArk Major Toht]] is the Baby-Eating Bishop of Bath and Wells! Eep.
** Angus Deayton makes an appearance in season 1.
** [[Film/ANewHope Jek Porkins]] is the drunk friar in "Beer".
** [[Series/TheHitchhikersGuideToTheGalaxy Arthur Dent]] is Sir Walter Raleigh in "Potato". So despite their both being friends of Creator/DouglasAdams, this is the first and only time Arthur Dent and the Fourth Doctor have ever met on-screen - without his involvement!
** [[Series/TheHitchhikersGuideToTheGalaxy Ford Prefect]] is the Standing at the Back Dressed Stupidly and Looking Stupid candidate as well as the Speaker of the House of Commons (the latter is [[TheVoice only heard near the end]]) in "Dish and Dishonesty".
** The two actors in "Sense and Senility" are [[Radio/RoundTheHorne Julian]] and his friend... [[Series/AlloAllo Monsieur Alphonse.]]
** [[DalzielAndPascoe Det. Supt. Andy Dalziel]] (or, alternatively, [[Film/AClockworkOrange Dim]]) is bluff Northern industrialist Mr. Hardwood in "Amy and Amiability".
** Standup comic and [[Radio/ImSorryIHaventAClue "singer"]] Jeremy Hardy is Blackadder's jailer in "Corporal Punishment".
** [[Series/AsTimeGoesBy Lionel Hardcastle]] (or, alternatively, [[Series/FawltyTowers Dr. Price]]) is Field Marshal Haig.
* WordOfGod: Turnips are mentioned a lot, from the first series on. In series three, they become Baldrick's only ambition in life. The creators say this is because someone confused them with parsnips, which explains the joke about their shape in series two.

!!Present in ''The Black Adder''
* OldShame: Rowan Atkinson and producer John Lloyd spend a significant amount of time badmouthing this series in the documentary included on the DVD boxset, calling it "pretty, but dreary to watch."
* ThePeteBest: BrianBlessed (Richard), Elspet Gray (Gertrude), Robert East (Henry) all qualify, as none of them would return for the later, more popular incarnations of the series (Blessed was asked back for one-off appearances in the third and fourth series, but was unavailable on both occasions).
* WhatCouldHaveBeen: The original pilot episode was much more similar what the later ''Blackadder'' installments would be like, but ExecutiveMeddling resulted in the version of ''The Black Adder'' that we know and... well, treat as a valued and respected ''friend'', but not really love, per se. Most fans believe that had the finished series combined the pilot episode's characterisations with the cast that we ended up with, it would have been vastly superior.
** In ''The Archbishop'', [[Series/SteptoeAndSon Wilfrid Brambell]] was originally cast to play the dying landowner, the Duke of Winchester in the opening scene. However, delays while filming the scene led to Brambell getting impatient and storming off the set, resulting in his speedy replacement by [[Series/DoctorWho William Russell]].

!!Present in ''Blackadder II''
* IronyAsSheIsCast: Miriam Margolyes, who played the Puritanical Lady Whiteadder, is not only openly gay but Jewish.
* NamesTheSame: Mr Ploppy and Mistress Ploppy are not married or related in any way, but have the same name by pure coincidence. Baldrick then offers to change his name to Ploppy "if it'll make things easier" on Edmund. For the rest of the episode, Mr. Ploppy refers to Baldrick as "Young Ploppy".
** And of course, Ploppy's father Daddy Ploppy, AKA "Ploppy the Slopper".
* WhatCouldHaveBeen: BrianBlessed claims that the original plan was that he would have played Queenie. And been madly in love with Edmund. It's quite a terrifying idea.

!!Present in "Blackadder the Third"

!!Present in ''Blackadder Goes Forth''
* ActorAllusion: In "Captain Cook", Melchett tells George that his [[Series/JeevesAndWooster Uncle Bertie]] sends his regards. ''Blackadder'' predates ''Jeeves and Wooster'', so it's a ''prescient'' Actor Allusion!
* RealitySubtext: Creator/StephenFry's homosexuality is amusingly alluded to by some of General Melchett's actions.
* TroubledProduction / WagTheDirector: According to StephenFry and Tony Robinson, there was a lot of friction between the cast and writers during the making of this series, with the actors frequently rewriting the script on the set, which the two have admitted doing themselves. The resulting atmosphere on-set -- together with producer John Lloyd leaving the BBC and the knowledge that any hypothetical ''Blackadder 5'' would be eviscerated by the critics if it was even slightly worse than the previous series -- made it certain that this would be the final ''Blackadder'' production until ''Back & Forth'' ten years later.