The group, which has around 500 employees working primarily in Spain, Portugal, and Latin America, said growth would have been 20.8 per cent without taking into consideration exchange rate differences, particularly in Mexico and Argentina.
Revenue in Latin America, which now accounts for 62 per cent of the total, grew 11 per cent. In the Iberian offices (Barcelona, Lisbon, and Madrid), revenue increased 16 per cent.
The agency said it did not disclose profit figures, but underlying profit (EBIT) margin is "good, just like the ones of the past years".
The agency plans to double the volume of business over the next five years. In 2016 Llorente & Cuenca launched in New York, in alliance with financial comms agency Abernathy MacGregor, and also opened in Cuba.
On its current expansion strategy, the company said: "We continue our acquisition plan and hope that we can make big announcements this year, if conversations and negotiations keep ongoing and close positively."
José Antonio Llorente, founding partner and chairman of Llorente & Cuenca, said: "2016 was a good year for the company because we were able to continue our trend of sustained growth, and we plan to maintain this rate as we double our volume of business over the next five years.
"We are committed to being client focused. We want clients to be a decisive factor in our business, and although they are already aware of this, we are going to make it even more evident in the future. It was also an important year since we expanded our business to New York and Cuba, which has further strengthened our top position as the leading communications consultancy in Spain, Portugal and Latin America."
In December, the group appointed Jordi Sevilla, who has held various roles in the Spanish Government including chief of staff to the minister of economy and finance and also the minister of public administration, to develop and co-ordinate its new Economic Context arm. This division focuses on expanding the agency's range of services.
Llorente & Cuenca was the 53rd biggest agency in the world in 2015, according to PRWeek's Global Agency Business Report.
This article was updated on Monday afternoon with additional information about profit margin and acquisition plans.