Connector for circuit elements of hydraulic or pneumatic systems, comprising: - a first connecting body extending along an development axis: - a second connecting body extending along an development axis; wherein said first connecting body and said second connecting body can be installed on respective portions of said circuit elements and are configured to provide a reversible fluid connection between said circuit elements wherein said connector, comprises: - a first coupling member comprising a male tubular portion on said first connecting body and a respective female tubular portion on said second connecting body to realize a sealed fluid connection by inserting said male tubular portion into a cavity of said female tubular portion configured to guide said male tubular portion; - a second coupling member comprising at least one protuberance on an external surface of said first connecting body and a respective groove on said second connecting body to realize a reversible mechanical connection between said first connecting body and said second connecting body wherein said protuberance is configured to fit into said groove and prevent an axial extraction between the first connecting body and the second connecting body; - a third coupling member comprising on said first connecting body at least one flexible tab having a projection on the outer surface and an opening on an external surface of said second connecting body adapted to contain said projection to prevent a relative rotation between the first connecting body and the second connecting body around the respective development axes (X, Y), said first connecting body is at least partially insertable in said second connecting body to realize a complete axial coupling of the first connecting body with the second connecting body, characterized in that said groove and said opening are connected to each other and wherein said groove extends along a circumferential portion of said second connecting body and has a width equal to that of said protuberance of the first connecting body, width measured in the direction of the development axis and/or the development axis, said opening having a width equal to that of the projection of the first connecting body, width measured in the direction of the development axis and/or of the development axis. - a first connecting body extending along an development axis: - a second connecting body extending along an development axis; - a first coupling member comprising a male tubular portion on said first connecting body and a respective female tubular portion on said second connecting body to realize a sealed fluid connection by inserting said male tubular portion into a cavity of said female tubular portion configured to guide said male tubular portion; - a second coupling member comprising at least one protuberance on an external surface of said first connecting body and a respective groove on said second connecting body to realize a reversible mechanical connection between said first connecting body and said second connecting body wherein said protuberance is configured to fit into said groove and prevent an axial extraction between the first connecting body and the second connecting body; - a third coupling member comprising on said first connecting body at least one flexible tab having a projection on the outer surface and an opening on an external surface of said second connecting body adapted to contain said projection to prevent a relative rotation between the first connecting body and the second connecting body around the respective development axes (X, Y), said first connecting body is at least partially insertable in said second connecting body to realize a complete axial coupling of the first connecting body with the second connecting body, characterized in that said groove and said opening are connected to each other and wherein said groove extends along a circumferential portion of said second connecting body and has a width equal to that of said protuberance of the first connecting body, width measured in the direction of the development axis and/or the development axis, said opening having a width equal to that of the projection of the first connecting body, width measured in the direction of the development axis and/or of the development axis.