The boundary-layer transition and stability characteristics of sharp cones at angle-of-attack are investigated with measurements at Mach 10 in the Arnold Engineering Development Complex (AEDC) Hypervelocity Wind Tunnel 9 on a 1.5-m long, 7-deg cone at unit Reynolds numbers between 1.8 and 15 million per meter. The transition location is determined with coaxial thermocouples and temperature sensitive paint, and stability measurements are obtained using high-frequency response pressure sensors. The measurements are used to validate the STABL-3D linear stability theory (LST) code at angles-of-attack up to 6-deg. The computations are found to reproduce the experimental trends regarding the effect of angle-of-attack on the growth of 2nd mode waves. The amplitude of the 2nd mode waves near breakdown on the leeward and windward meridians scale linearly with edge Mach number. The initial amplitudes estimated using linear stability computations are found to scale with Pitot noise in the unstable 2nd mode frequency band. Linear stability computations along with the ability to correlate initial 2nd mode amplitudes to tunnel noise and to correlate maximum 2nd mode amplitudes to edge Mach number enables the use of Mack’s amplitude method to predict 2nd mode transition. This methodology is investigated to accurately predict sharp cone boundary layer transition at 0-deg AoA. Extension to sharp cones at angle-of-attack is expected to be straightforward.