A MEMS tri-axial accelerometer, provided with a sensing structure comprising: a single inertial mass, having a main extension in a horizontal plane (xy) defined by a first horizontal axis (x) and a second horizontal axis (y) and internally defining a first window that traverses it throughout a thickness thereof along a vertical axis (z) orthogonal to said horizontal plane (xy); and a suspension structure, arranged within said first window and configured to elastically couple said inertial mass to a single anchorage element, fixed with respect to a substrate and arranged within said window, so that said inertial mass is suspended above the substrate and is able to carry out, by the inertial effect: a first sensing movement in a first sensing direction (x) parallel to said first horizontal axis (x) following upon detection of a first acceleration component (a x); a second sensing movement along a second sensing direction (y) parallel to said second horizontal axis (y) following upon detection of a second acceleration component (a y); and a third sensing movement along a third sensing direction (z) parallel to said vertical axis (z) following upon detection of a third acceleration component (a z), wherein said suspension structure comprises at least one first decoupling element configured to decouple at least one of said first, second, and third sensing movements from the remaining sensing movements of said inertial mass, and wherein said suspension structure comprises first elastic elements (10a, 10b) configured to elastically couple said first suspension element to said anchorage element, and second elastic elements (12a, 12b), configured to elastically connect said first suspension element to said inertial mass; wherein said second elastic elements (12a, 12b) are configured to enable and control, independently and exclusively, said at least one sensing movement, characterized in that said suspension structure further comprises a second decoupling element configured to decouple at least one further of said first, second, and third sensing movements, different from said at least one sensing movement, from the remaining sensing movements. a single inertial mass, having a main extension in a horizontal plane (xy) defined by a first horizontal axis (x) and a second horizontal axis (y) and internally defining a first window that traverses it throughout a thickness thereof along a vertical axis (z) orthogonal to said horizontal plane (xy); and a suspension structure, arranged within said first window and configured to elastically couple said inertial mass to a single anchorage element, fixed with respect to a substrate and arranged within said window, so that said inertial mass is suspended above the substrate and is able to carry out, by the inertial effect: a first sensing movement in a first sensing direction (x) parallel to said first horizontal axis (x) following upon detection of a first acceleration component (a x); a second sensing movement along a second sensing direction (y) parallel to said second horizontal axis (y) following upon detection of a second acceleration component (a y); and a third sensing movement along a third sensing direction (z) parallel to said vertical axis (z) following upon detection of a third acceleration component (a z), wherein said suspension structure comprises at least one first decoupling element configured to decouple at least one of said first, second, and third sensing movements from the remaining sensing movements of said inertial mass, and wherein said suspension structure comprises first elastic elements (10a, 10b) configured to elastically couple said first suspension element to said anchorage element, and second elastic elements (12a, 12b), configured to elastically connect said first suspension element to said inertial mass; wherein said second elastic elements (12a, 12b) are configured to enable and control, independently and exclusively, said at least one sensing movement, characterized in that said suspension structure further comprises a second decoupling element configured to decouple at least one further of said first, second, and third sensing movements, different from said at least one sensing movement, from the remaining sensing movements.