Richard Ryther Steer Bowker (30 August 1815 – 3 April 1903) was an Australian mariner, physician, surgeon and politician.

Bowker was the son of Thomas Dawson and Elizabeth Steer and born at Campsall, Yorkshire, England.

He was awarded diplomas in botany and materia medica in Paris in 1836 and an MD from the University of St Andrews in 1839.

He visited Australia in the emigrant ship the Shepherd and then migrated to Melbourne, Colony of New South Wales, in the Georgiana in February 1841.

In New South Wales, Bowker was appointed as a medical practitioner to the Loyal Union Lodge in Newcastle in 1842, resigning in 1844.