Leendert Ginjaar (28 May 1928 – 17 September 2003) was a Dutch politician of the People's Party for Freedom and Democracy (VVD) and chemist.

After the election of 1977 Ginjaar was appointed as Minister of Health and Environment in the Cabinet Van Agt-Wiegel, taking office on 19 December 1977.

Ginjaar served as acting Minister for Science Policy from 1 April 1979 until 3 May 1979 following the death of Rinus Peijnenburg.

Ginjaar was elected as a Member of the Senate after the Senate election of 1981, taking office on 25 August 1981 serving as a frontbencher chairing the parliamentary committee for Higher Education and Science Policy and the parliamentary committee for Housing and Spatial Planning and spokesperson for the Environment, Higher Education and Agriculture.

In November 2002 Ginjaar announced his retirement from national politics and that he wouldn't stand for the Senate election of 2003 and continued to serve until the end of the parliamentary term on 10 June 2003.