Bana Alabed shared a short video of herself and the Mean Girls star.
They were in Ankara, Turkey, where they met President Recep Tayyip Erdogan.
Ms Lohan, who has been in the country for the past few days, says in the video that the pair are "sending lots of love and life and blessings" to refugees and people in Syria.
The short clip shows Bana hugging the actress, who tells the camera: "We want to send to all of the people in Syria and Aleppo suffering and to all the refugees we are here supporting you and you can hang on and be strong just like Bana has."
She adds "inshallah", which means "if God wills" in Arabic.
Bana rose to fame after documenting on Twitter her daily life in rebel-held East Aleppo, with the help of her mother.
The seven-year-old recently penned an open letter to new US President Donald Trump, asking him to open the country to refugees.
Ms Lohan became a film star aged 11 when she starred in Disney's The Parent Trap, but her career has been marred in recent years by a series of scandals.
Rumours began circulating this week the actress may have converted to Islam, after she was spotted in Turkey wearing a hijab.
The actress also appears to have deleted all of her posts on Twitter and Instagram, changing her bio on the latter to read "alaikum salam", which means "peace be upon you" in Arabic.

Poole, 19, moved to Old Trafford in 2015 from Newport County, where he played under current Cobblers boss Justin Edinburgh.
But his only United appearance to date was as a late substitute in the Europa League in February 2016.
The Wales Under-21 international comes in as competition for centre-backs Ash Taylor and Leon Barnett.
Edinburgh said: "He is a central defender who is comfortable on the ball. He is strong, he leaps well and he has all the attributes to be a top, top player.
"He is mobile and he will complement the other defenders we have at the club well."
Find all the latest football transfers on our dedicated page.

West Sussex Fire and Rescue said crews were called to a "ferocious fire" in the kitchen of the property in Harwood Road, Littlehampton, at 12:10 BST.
Police said a woman inside the house died, while two other adults were taken to hospital suffering from the effects of smoke inhalation.
The cause of the fire is currently being treated as unexplained.
Anyone who saw what happened at the time the fire broke out or who may have any other information is asked to contact Sussex Police.
The little girl who captured the world's heart tweeting about her life in East Aleppo has made a new friend - US actress Lindsay Lohan.
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League One side Northampton Town have signed young Manchester United defender Regan Poole on a season-long loan.
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A woman has died and two other people have been injured following a fire at a terraced house in West Sussex.