We report a femtosecond optical parametric oscillator (OPO) based on the nonlinear material $\mathrm{Bi}{\mathrm{B}}_3{\mathrm{O}}_6$ . The OPO is synchronously pumped in the blue by the second harmonic of a Kerr-lens-mode-locked Ti:sapphire laser. It can provide wide and continuous tuning across the entire green–yellow–orange–red spectral range with a single crystal and a single set of mirrors. Using a $500\mu \mathrm{m}$ $\mathrm{Bi}{\mathrm{B}}_3{\mathrm{O}}_6$ crystal and collinear type I $(e+e\to o)$ phase matching in the optical $yz$ plane, a signal wavelength range of $480–710\mathrm{nm}$ is demonstrated with angle tuning at room temperature at average output powers of $270\mathrm{mW}$ . With $220\mathrm{fs}$ blue pump pulses, near-transform-limited signal pulses of $120\mathrm{fs}$ duration have been obtained at $76\mathrm{MHz}$ repetition rate.