George Holbrook Jackson (31 December 1874 – 16 June 1948) was a British journalist, writer and publisher. He was recognised as one of the leading bibliophiles of his time.
Holbrook Jackson was born in Liverpool, England. He worked as a clerk, while freelancing as a writer. Around 1900 he was in the lace trade in Leeds, where he met A. R. Orage; together they founded the Leeds Arts Club. At that time Jackson was a Fabian socialist, but also influenced by Nietzsche. It was Jackson who introduced Orage to Nietzsche, lending him a copy of Thus Spoke Zarathustra in 1900.
Later they separately moved to London as journalists. In 1906, shortly after arriving in the capital, Jackson suggested founding a similar group to the Leeds Arts Club, the Fabian Arts Group. This eventually led to a split from the Fabian Society, whose interest was economic and political. In 1907, Jackson and Orage bought The New Age, a struggling Christian Socialist weekly magazine, with finance from Lewis Wallace and George Bernard Shaw.
Initially Jackson and Orage co-edited, with Jackson setting the editorial line with Cecil Chesterton and Clifford Sharp (later the editor of the New Statesman). In 1908 Jackson left and Orage continued as sole editor. Around this time, Orage's wife left him for Jackson, but refused to divorce Orage.
From 1911 Jackson had an editorial position on T. P. O'Connor's T.P.'s Weekly, a newspaper with a strong literary emphasis. He took over as editor from Wilfred Whitten in 1914. Later he bought the publication, and converted it into his own literary magazine, To-Day, which was published 1917 to 1923, when it merged with Life and Letters.