This episode marks the introduction of a Low Valyrian language (sometimes just called "Valyrian" for short), spoken by Missandei and others in Slaver's Bay. High Valyrian ceased to be a living language after the fall of Valyria four hundred years ago, and became a lore-language similar to Latin in Medieval Europe. The Low Valyrian languages are heavily derived from High Valyrian, similar to how Latin influenced the Romance languages Spanish, French, Italian, Portuguese and Romanian.
This episode contains a rare, if not the only instance of Cersei (Lena Headey) and Bronn (Jerome Flynn) appearing (briefly) in the same shot. Headey and Flynn were once in a relationship that ended so badly that both reportedly had clauses in their contracts, stating that they were not to appear in scenes together, and should also be kept apart on set. Although Flynn once denied in an interview that this was the case, all further interaction occurring between Bronn and Cersei for the rest of the series always happens off-screen.
The episode title "Valar Dohaeris" is an expression in High Valyrian, the meaning of which is "all men must serve". It is a customary saying in Essos, and is the traditional answer to the expression "Valar Morghulis" ("all men must die"), which was also the title of the previous episode (Valar Morghulis (2012)). Both terms aren't actually used on-screen until The Climb (2013).
Cersei's comment to Tyrion, "They say you'd lost your nose", is an in-joke for those who have read the books, where apart from a large gash in his face, most of Tyrion's nose was cut off when Mandon Moore attempted to kill him. For the series, only the facial scar was kept; the nose injury would have required the visual effects artists to digitally remove Peter Dinklage's nose in all of his scenes to follow, which would have been too time-consuming and expensive.
The episode is dedicated to the memory of cinematographer Martin Kenzie, who died of cancer while the third season was being filmed on July 16, 2012.