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.
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.