After the prolonged break caused by the COVID-19 pandemic, Selby participated in the 2020 Championship League, going out of the tournament after the first group stage. He qualified for the 2020 Tour Championship ranked third on the one-year ranking list. He beat Yan Bingtao 9–6 in the quarter-finals before being defeated 2–9 by Mark Allen in the semi-finals. At the World Championship, Selby defeated debutant Jordan Brown 10–6 in the first round, Noppon Saengkham 13–12 in the last 16, and Neil Robertson 13–7 in the quarter-finals. In the semi-final, he met Ronnie O'Sullivan, who took a 5–3 lead after the first session, but Selby won the second session to take a 9–7 lead. During the third session, he established a 13–9 advantage before O'Sullivan won the last two frames of the session. Selby then took a 16–14 lead, leaving himself one frame away from his fifth World Championship final, but he lost the final three frames of the match. After the game, Selby accused his opponent of being "disrespectful" after O'Sullivan had played several hit-and-hope shots while being snookered. Selby finished the season as world number four.