The following is a timeline of the Syrian civil war for 2020. Information about aggregated casualty counts is found at Casualties of the Syrian civil war.
January
Idlib
The Syrian government continued to launch major attacks on rebel groups in Northwestern Syria ("Greater Idlib"), with Russian air support. Continued operations have caused over 200,000 refugees to flee the area, with many fleeing to Turkey.
On 11 January, Russia announced that a ceasefire had been agreed to in the area of Idlib and Northwest Syria, between Russia, Syria, Syrian rebels and Turkey. This was due to requests by Turkey for a ceasefire, in order to stop the flow of Syrian refugees into Turkey. However, some regional news outlets reported that Syria launched further attacks near Idlib, in Ma'arrat al-Nu'man District and the villages of Maar Shoreen, Talmenes, and Maar Shamshah, even after the ceasefire had officially begun.
On 21 January, Russian warplanes targeted a farm on the outskirts of the Kafar Taal village, in western Aleppo province, killing nine civilians, among them six children, and also targeted areas in the southern and south-eastern countryside of Idlib, inflicting damage to property.
On 28 January, the Syrian Arab Army captured the strategic city of Ma'arrat al-Nu'man. A war monitor and government media added that the Syrian army went into the city under the protection of heavy air strikes.
Northeastern Syria
According to Andalou Agency, on 18 January, U.S. troops blocked a Russian convoy from entering Rmelan, where the U.S. is protecting oil fields under SDF administration. Tension occurred between the two groups as U.S. soldiers asked the Russian soldiers to return to the Amuda district in northwest of Al-Hasakah Governorate.
There was a dispute in the UN Security Council over the re-authorization for border-crossing points into Syria to deliver aid. The existing authorization expired on 10 January 2020. In December 2019, China and Russia vetoed a proposal to renew all four existing crossing points, which are located in Iraq, Jordan, and Turkey; they wished to eliminate all crossing points except the ones in Turkey. By January 2020, the dispute was ongoing.
February
On 1 February, four officers from the K and S units of Russia's Federal Security Service were reported killed near Aleppo.
Al-Tanf
Around 16 February, an Iranian-backed proxy group reportedly approached Al-Tanf, and were then repelled by the U.S.-partnered Maghaweir al-Thowra.
Idlib and Aleppo
According to the UK-based Syrian Observatory for Human Rights (SOHR), by 6 February, the Syrian Army had captured 139 (including areas captured last year) towns, villages and hilltops, including the strategic city of Ma'arrat al-Nu'man, towns and villages of Al-Tah, Jarjnaz, Tell Mannas, Kafr Rumah, Khan al-Sabil, Hish, Sarmin and Afs and Turkish observation posts at Sarman, Maar Hattat, Tell Touqan, Rashidin in Western Aleppo and 4 posts inside the encircled Saraqib pocket. Humanitarian organizations called for a ceasefire in Idlib after 520,000 people had been displaced from their homes.
On 10 February, pro-Syrian government and Iranian-backed militias including Shabiha were filmed desecrating the graves and exhuming the bodies of opposition fighters and those affiliated with them, in a series of clips circulated on social media during the two days prior, in southern Idlib province, and holding skulls of opposition fighters and civilians and mocking them.
On 18 February, the United Nations High Commissioner for Human Rights expressed her concerns over the increase in fighting in northwest Syria and blamed the Syrian government and Russia for intentionally targeting civilians.
On 20 February, Turkish-backed rebels launched another counteroffensive on Nayrab with Turkish artillery support. Turkish commandos were also reported to have been operating alongside rebels in the assault on the town. A Russian UAV was reported to have been shot down during the initial shelling and rocket strikes. Russian planes provided air support to the pro-government forces and struck positions of the advancing rebels. Additional shelling on nearby towns on both the government-controlled and opposition-controlled sides of the frontline were reported, with both Russian and Turkish forces involved in air and artillery support roles respectively. During the battle, rebels reportedly attempted to shoot down a Russian Su-24 using Turkish-provided MANPADS.