Pakistan–Sri Lanka relations refer to bilateral relations between Pakistan and Sri Lanka. both countries are in the South Asia region. The earliest proper diplomatic and trade contacts between Pakistan and Sri Lanka (then Ceylon) date back as early as 1948. In the past, Pakistan assisted the Government of Sri Lanka in supplying High-Tech military equipment to the Sri Lankan army in the civil war against the Liberation Tigers of Tamil Eelam. The relationship also fosters on strong mutual Sino-Pakistan and Sino-Sri Lankan relationship, as China maintains strong mutual interest in the economic and military development of Sri Lanka and Pakistan, Both Pakistan and Sri Lanka are also members of SAARC.Relations which are generally warm have gone into strong tie recently.
There is a Pakistani embassy located in Colombo and a Sri Lankan embassy situated in Islamabad.
Pakistan is the second largest trading partner of Sri Lanka in South Asia. Sri Lanka was the first country to sign a Free Trade Agreement with Pakistan, which became operational from June 12, 2005. 4,000 items can be imported to Pakistan from Sri Lanka. Bilateral trade between the 2 countries was US$400 million in early 2010, and is expected to increase to US$2 billion by 2012. In November 2010, President Asif Ali Zardari mulled a 250 million dollar export credit line that Pakistan would extend to Sri Lanka. Trade between the two countries reached $500 million by the end of 2010
Recently, the Sri Lankan Airlines has expressed an interest in expanding its operations in multiple cities in Pakistan and has also invited the Pakistan International Airlines to operate more flights to Sri Lanka. Sri Lankan Airlines chief marketing officer GT Jeyaseelan remarked that "Sri Lanka and Pakistan are two close, friendly neighbours," and that he looked forward to enhancing cooperation between the two airlines.
Sri Lanka started buying arms and ammunition from Pakistan in a big way from 1999. The total purchases until December 2007 were worth $50 million while there has been a sudden jump in the quantity of merchandise ordered in 2009 and the amount has been tripled. With India reluctant to sign a Defense Cooperation Agreement with Sri Lanka and unwilling to supply it with the kind of weapons it is looking for, Colombo has turned increasingly to Pakistan. There are segments of opinion in Sri Lanka that are in fact in favor of the government finalizing a defense cooperation agreement with Islamabad.
In May 2000, President Musharraf of Pakistan supplied millions of dollars of much-needed weapons to the Sri Lankan government, when separatist Tamil Tiger rebels were about to recapture their former capital of Jaffna. In August 2006, suspected LTTE rebels attempted to assassinate Pakistan's ambassador to Sri Lanka, Bashir Wali Mohamed, with a claymore mine in Colombo. Mohamed was not hurt but seven others died. In May 2008, Lt. Gen Sarath Fonseka of the Sri Lanka Army held talks with his Pakistan Army counterparts regarding the sale of military equipment, weapons and ammunition. The supplies of 22 Al-Khalid MBTs to the Sri Lanka Army was finalized during these talks in a deal worth over US$100 million.
In April 2009, Sri Lanka requested $25 million worth of 81 mm, 120 mm and 130 mm mortar ammunition to be delivered within a month. During a state visit by President Asif Ali Zardari to Sri Lanka in Nov 2010, Sri Lanka evinced interest in purchase of Pakistani al-Khalid Main Battle Tanks, light weapons and ammunition, and the Sino-Pak joint venture product JF-17 Thunder aircraft. Pakistan has also offered to train Sri Lankan spies for intelligence gathering purposes Apart from traditional military assistance to Sri Lanka, Pakistan has also offered to train Sri Lankan police and intelligence service officers
Sri Lanka has also shown interest in signing a nuclear deal with Pakistan, snubbing a similar offer from India. The snub is thought to come in the wake of India's vote against Sri Lanka on the Tamil issue at the UN human rights council.
In April, 2015 Sri Lanka signed a nuclear energy deal with Pakistan.
On 30th September, 2016, in the wake of India-Pakistan conflict after the Uri attack in India, Sri Lanka pulled out of the 19th South Asian Association for Regional Cooperation (SAARC) Summit in Pakistan. The Ministry of Foreign Affairs in Colombo said that the prevailing environment in that region was not conducive for holding the summit.
Shortly after the defeat of the Tamil Tiger rebels in Sri Lanka, Islamabad congratulated Sri Lanka and the Deputy Minister of Foreign Affairs Hussein A. Bhaila of Sri Lanka called Pakistan a true friend saying:
"The government and the people of Sri Lanka have considered Pakistan as a true friend of Sri Lanka, which has always stood by it in times of need..."
In June 2011, Pakistan presented the Government of Sri Lanka with a number of Buddhist relics from Pakistan's past. A former Pakistan High Commissioner, Seema Ilahi Baloch, also sponsored the construction of a school in Gampala District.