The main stock index ended 0.06 percent, or 3.94 points, higher at 7,100, its highest close since Oct. 2.
Analysts said trading was dull amid uncertainty ahead of Prime Minister Ranil Wickremesinghe's policy statement next month outlining his government's economic priorities.
Turnover stood at 988.3 million rupees ($7.06 million), compared with this year's daily average of 1.11 billion rupees.
Foreign investors, who have been net sellers of 2.80 billion rupees worth of equities so far this year, bought a net 245.9 million rupees worth of shares on Monday.
Shares of Sri Lanka Telecom Plc rose 2.12 percent, while Ceylon Tobacco Company Plc gained 1.06 percent.
(reuters.com)