The income tax laws of about sixty countries may be said to be of a style or type that derives from or is associated with the income tax law of Britain. Most all of these countries had some form of colonial connection with Britain. It is doubtless that many other income tax laws, which would not typically be considered to be from the ‘British family’, were also influenced at various stages by the British income tax, typically at their inception. It is also doubtless that the British income tax, at least indirectly, if not directly, was influenced at its modern inception in 1799 by the tax laws of other European countries and, perhaps, its colonies. Further, it is certain that much of the content of Britain's 1799 income tax law was derived directly from earlier English direct tax laws stretching back 700 years and more.

To a more limited extent, the same is true of former British colonies. The taxes that ultimately developed into or were the precursors of the income tax were influenced by a greater variety of factors. The early tax systems of the colonies were influenced by each colony's own peculiar circumstances, other colonies with which they were affiliated, other colonial powers to which they may have been subject and, of course, Britain. Importantly, however, colonies were most prone to importation of tax laws in the early days of their founding.