Laurynas Gucevičius (Polish: Wawrzyniec Gucewicz; 1753–1798) was an 18th-century architect born in the Polish-Lithuanian Commonwealth, the Grand Duchy of Lithuania, and most of his designs were built there.
In his youth he travelled to Italy and Paris and other countries in Western Europe, where he studied architecture under the notable contemporary neo-classical French architects, Jacques-Germain Soufflot and Claude Nicolas Ledoux. Later he was appointed professor at the Jesuit Academy of Vilnius, the predecessor of the University of Vilnius. Among the best known of his works are the Vilnius Cathedral, the town hall and the summer palace of bishops in Verkiai. The monumentality of forms and volume, the harmony with surroundings and a special treatment of antique architectural forms are the characteristics of his style.
Born in the village of Migonys near Kupiškis, in the Grand Duchy of Lithuania. His father was a peasant, Simonas Masiulis, sometimes also called by the name of Stuoka after his stepfather. He was baptized as Laurynas Masiulis. His mother, Kotryna Žekonytė Masiulienė died early in his youth, and her relative and his godmother Anna Gucewicz née Baltušytė (Lithuanian: Ona Baltušytė-Gucevičienė, supported him and financed his studies. After her he changed his surname to Gucevičius. He attended local schools at Kupiškis and Palėvenė and then the gymnasium in Panevėžys. In 1773 he joined the Academy of Vilnius. He studied engineering, attended the lectures on architecture held by Marcin Knackfus. Around that time, he also became a missionary monk.