Williams lost 1–5 to Judd Trump in the quarter-finals of the Shanghai Masters. He reached the final of the non-ranking General Cup, where he was defeated 3–7 by Marco Fu.&lt;ref name="2015/16"&gt;&lt;/ref&gt; He drew Ronnie O'Sullivan in the first round of the Masters and was 4–2 ahead. However, the match went to a deciding frame in which Williams missed a risky plant and lost 5–6. He lost in the fourth round of the Welsh Open 2–4 to Mark Selby and in the first round of three other ranking events and in qualifying for the China Open. Williams saw off Graeme Dott 10–4 and Michael Holt 13–8 to reach the quarter-finals of the World Championship for the first time in five years. However, he was then thrashed 3–13 by Ding Junhui in the quarter-final, with a session to spare.