Merve Buyuksarac, 27, was found guilty of insulting a public official for postings she made on social media. She denied insulting Mr Erdogan.
Her lawyer says he will file a formal objection to the verdict and take the case to a higher court.
Rights groups have criticised Turkey for backtracking on freedom of speech.
Almost 2,000 people, including celebrities and schoolchildren, have been prosecuted in Turkey for insulting the president since he came to office in 2014, under a previously little-used law.
Merve Buyuksarac, the 2006 Miss Turkey, was briefly detained last year for sharing a satirical poem on her Instagram account in 2014.
The posting, an adaptation of the Turkish national anthem, was shared thousands of times on social media, and it was considered by prosecutors to be insulting to Mr Erdogan, who was then prime minister.
Her sentence was suspended on condition that she does not reoffend within the next five years.
The model's lawyer, Emre Telci, told the Associated Press news agency: "These insult trials are being initiated in series, they are being filed automatically.
"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."
Mr Erdogan's lawyer, Hatice Ozay, said in court the post had gone beyond "the limits of criticism" and amounted to an "attack against my client's personal rights".
Human rights activists say Mr Erdogan is using the law to silence and intimidate critics, including journalists, academics and ordinary citizens.
The president caused uproar last month when he filed a criminal complaint against a German satirist in a case that prompted a debate over freedom of speech in Germany.
A Turkish court has convicted a former Miss Turkey of insulting President Recep Tayyip Erdogan, giving her a 14-month suspended prison sentence.