"An Englishman, an Irishman and a Scotsman" is the opening line of a category of joke in Ireland and the United Kingdom. The nationalities involved may vary, though they are most usually restricted to those within the UK and Ireland, and the number of people involved is usually three or sometimes four. In Ireland, the characters are sometimes called "Paddy Irishman (or a Corkman), Paddy Englishman, and Paddy Scotsman". The punchline is usually based around the Irishman's stupidity, the Scotsman's meanness (or frugality) or the Englishman's snobbishness. Sometimes, when the joke requires four people, a Welshman is brought into the joke.
The "3 nationalities" joke format is also very common in other countries. In these cases, the two foreigners are always portrayed as cocky, stupid and naïve, while the same nationality person is smart, practical and, ultimately, victorious.
Such jokes in Canada usually substitute the supposedly stupid Irishman with Newfie (pejorative term for someone who is from Newfoundland).
In The Netherlands the joke is usually presented as "A Dutchman, a German and a Belgian...",
in Turkey as "An Englishman, a Frenchman, and Temel (a fictional character from Black Sea Region of Turkey)...",
in France as "A Frenchman, a Belgian and a Quebecois",
in Egypt as "A Frenchman, a Belgian and a Sa'idi",
in Spain as "An Englishman, a Frenchman and a Spaniard",