The year 1986 in science and technology observed many events, some of which are included in the list below.

Astronomy and space exploration

• January 24 - Voyager 2 space probe makes first encounter with Uranus
• January 28 - Space Shuttle Challenger explodes on launch, killing all seven astronauts aboard.
• February 19 - The Soviet Union launches the Mir space station
• March 8 - Japanese spacecraft Suisei flies by Halley's Comet, studying its UV hydrogen corona and solar wind.

Biology

• May: First reported methods for constructing a monoclonal antibody containing parts from mouse and human antibodies, a required first step toward the development of humanized antibodies used later as medical therapeutics (such as Infliximab).

Computer science

• April 3 - IBM unveils the PC Convertible, the first laptop computer.

Medicine

• FDA approval of the first monoclonal antibody drug, Muronomab-CD3 (also known as Orthoclone OKT3), for treatment of transplant rejection.^{Immunotherapy: past, present and future. Nature Medicine 9, 269-277.}