1921 was the 28th season of County Championship cricket in England. Australia emphasised a post-war superiority that it owed in particular to the pace duo of Gregory and McDonald. Having won 5-0 in Australia the previous winter, the Australians won the first three Tests of the 1921 tour and then drew the last two to retain the Ashes. It was the 29th test series between the two sides. The County Championship was won for the second year in succession by Middlesex County Cricket Club. Glamorgan County Cricket Club joined the championship for the first time.