Willem Leonard Oltmans (10 June 1925 – 30 September 2004) was a Dutch investigative journalist and author who did not hesitate to pro-actively intervene in international politics.
Due to the highly critical and opposite stance he often took towards Dutch global politics, as of 1956 the Dutch government conspired to keep him out of work. During a lingering lawsuit (1991–2000), involving the Royal family, parties agreed to a binding arbitration in which the state had to pay him 8 million guilders in damages in 2000 (approx. 4 million in 2000 US dollars, 3.6 million euros, over 5.6 million dollars these days). As an erudite orator Oltmans' straightforward and uncompromising behaviour made him a striking media personality and unique phenomenon in Dutch society.