Three decades after what is widely referred to as the transition from a First to a Second Nuclear Age, the world stands on the cusp of a possible Third Nuclear Age where the way that we conceptualise the central dynamics of the nuclear game will change again. This paradigm shift is being driven by the growth and spread of non-nuclear technologies with strategic applications and by a shift in thinking about the sources of nuclear threats and how they should be addressed, primarily, but not solely, in the United States. Recent scholarship has rightly identified a new set of challenges posed by the development of strategic non-nuclear weaponry (SNNW). But the full implications of this transformation in policy, technology and thinking for the global nuclear order as a whole have so far been underexplored. To remedy this, we look further ahead to the ways in which current trends, if taken to their logical conclusion, have the capacity to usher in a new nuclear era. We argue that in the years ahead, SNNW will increasingly shape the nuclear order, particularly in relation to questions of stability and risk. In the Third Nuclear Age, nuclear deployments, postures, balances, arms control, non-proliferation policy, and the prospects for disarmament, will all be shaped as much by developments in SNNW capabilities as by nuclear weapons. Consequently, we advocate for an urgent reassessment of the way nuclear order and nuclear risks are conceptualised as we confront the challenges of a Third Nuclear Age.