Vandals targeted Wied Għollieqa Environment Centre on Monday night, causing extensive damage.
The culprits hurled stones, smashing a glass door and window panes and damaging some of the furniture inside.
The centre is used by environment NGO Nature Trust (Malta) to welcome visitors to Wied Għollieqa Nature Reserve, which is located between the University of Malta in Msida, and Kappara.
Hundreds of students visit the centre every year to learn about biodiversity, sustainable development and climate change, among others.
Nature Trust (Malta) executive president Vincent Attard condemned the vandal attack, saying preparations were underway for the centre to start receiving students, as schools are about to re-open after the summer break.
The NGO said it spent thousands of euros on the maintenance of the nature reserve and the environment centre every year.
“Vandal attacks are a blow to the organisation, which does its best to manage sites such as Wied Għollieqa on very limited financial resources,” the NGO said.
Earlier this year, vandals also damaged information signs and trees, and drowned cats and other animals in the water reservoir used to water young trees.