Turkish Model Merve Buyuksarac has been found guilty of insulting a public official by an Istanbul court.
The sentence delivered on Tuesday was suspended on condition she does not repeat the act within the next five years. Buyuksarac has denied insulting Erdogan.
Insulting the president is a crime punishable by up to four years in jail in Turkey.
Free speech advocates say the law is being used aggressively to silence and intimidate critics.
Since Erdogan won the presidency in August 2014 Turkish prosecutors have opened over 1,800 cases concerning alleged insults. They include cases against cartoonists and journalists.
The prosecutors are pursuing their case against German comedian Jan Böhmermann for his controversial poem, read out on his TV show.
Buyuksarac and "the Master's Poem"
The 27-year old Buyuksarac - who was crowned Miss Turkey in 2006 - shared her poem on Instagram in 2014, when Erdogan was prime minister. Called "the Master's Poem," it refers to a high-level Turkish corruption scandal.
Erdogan, who was elected president in August 2014, is often called "Buyuk Usta" (the Big Master). Several thousand social media users also posted the poem, which is a satirical adaptation of the Turkish national anthem.
Hatice Ozay, Erdogan's lawyer, told the court that Buyuksarac's posts on social media could not be considered criticism but rather constituted an "attack against my client's personal rights."
Appeal to be lodged
Buyuksarac's lawyer, Emre Telci, said he would file a formal objection against the verdict and appeal her case at the Strasbourg-based European Court of Justice.
"These insult trials are being initiated in series, they are being filed automatically," Telci said. "Merve was prosecuted for sharing a posting that did not belong to her. My client has been convicted for words that do not belong to her."
Erdogan's lawyer, Hatice Ozay, argued in court that Buyuksarac's Instagram post had gone beyond "the limits of criticism" and amounted to "an attack" on the Turkish leader's personal rights.
The journalist Cengiz Candar also appeared in court in Istanbul on Tuesday accused of insulting Erdogan in a series of columns he wrote last summer criticizing Turkey's renewed conflict against Kurdish rebels. He faces up to four years in prison if found guilty.
Outside the courthouse, Candar told reporters: "These court cases must come to an end. Secondly, these trials must immediately end with acquittals so that the presidency of the Turkish Republic can preserve its respectability."
Candar's case was adjourned until September.
jbh/jm (Reuters, AP, AFP)