Recent progress in the development of superconducting nanowire single-photon detectors (SNSPDs) has delivered excellent performances, and has had a great impact on a range of research fields. The timing jitter, which denotes the temporal resolution of the detection, is a crucial parameter for many applications. Despite extensive work since their apparition, the lowest jitter achievable with SNSPDs is still not clear, and the origin of the intrinsic limits is not fully understood. Understanding its intrinsic behaviour and limits is a mandatory step toward improvements. Here, we report our experimental study on the intrinsically-limited timing jitter in molybdenum silicide (MoSi) SNSPDs. We show that to reach intrinsic jitter, several detector properties such as the latching current and the kinetic inductance of the devices have to be understood. The dependence on the nanowire cross-section and the energy dependence of the intrinsic jitter are exhibited, and the origin of the limits are explicited. System timing jitter of 6.0 ps at 532 nm and 10.6 ps at 1550 nm photon wavelength have been obtained.Since their first demonstration 1 , superconducting nanowire single-photon detectors (SNSPDs) have emerged as a key technology for optical quantum information processing 2 . Their low dark count rate, fast response time, small jitter, and high efficiency favours their use in various demanding quantum optics applications such as quantum key distribution 3 , quantum networking 4 , device-independent quantum information processing 5 , deep-space optical communication 6 , IR-imaging 7,8 , and integration in photonic circuits 9-11 .One advance in the SNSPD field has been the introduction of amorphous superconductors such as tungsten silicide (WSi) 12 and molybdenum silicide (MoSi) [13][14][15][16] . SNSPDs based on these materials currently have the highest reported system detection efficiencies (SDE) (93% for WSi 12 ). Their amorphous properties makes them materials of choice for applications where the film quality and yield are crucial, such as multi-mode coupled SNSPDs, or large arrays 17 .