Leonard Ludwik Straszyński was a Polish painter and lithographer.

He was born in Tokarówka in the Kiev Governorate, in what is now Ukraine. Son of Wilhelm Straszyński.

After completing his studies in Kiev, from 1847 he studied art at the Imperial Academy of Fine Arts in St. Petersburg. He studied painting with professor Alexei Markov. In 1850 he was awarded a small silver medal for the portrait of King Lear. In 1854 he was awarded a gold medal for the painting Death by Ricchio, which is characterized by exceptional expression. He graduated in 1855 with a great gold medal. He received a six-year scholarship abroad and left for Paris in 1856. Soon he moved to Brussels. He visited Germany and Italy (in 1860 he was in Rome

He obtained the title of academician at the Imperial Academy of Fine Arts in St. Petersburg in 1862. The academic museum exhibits his portraits of Cardinals Mazarin and Richelieu. He was a member of the Academia di Quiritta in Rome. Around 1867 he left for London, where he stayed until 1871. After returning to Poland, he lived in Warsaw and Żytomierz.