Athelstan Laurence Johnson Beckwith (20 February 1930 – 15 May 2010) was an Australian chemist.
In 1960, he won the Rennie Memorial Medal.
In 1961, he won a Nuffield Scholarship to study with Sir Derek Barton.
He was Professor of Organic Chemistry at the Australian National University, from 1981 to 1995.
In the 2004 Queen's Birthday Honours he was appointed an Officer of the Order of Australia for "service to science in the field of organic chemistry as a leading researcher and academic, and through the provision of advice to government and the wider community on scientific matters".