lenscov computes full‑sky and flat‑sky covariances of lensed cosmic‑microwave-background (CMB) and lensing power spectra. The package provides routines to analytically compute N0 and N1 biases, lensed CMB spectra (via series‑expansion or correlation‑function methods), and the auto- and cross‑covariances of CMB lensed spectra and the lensing potential up to second order in the lensing power spectrum. lenscov combines Python with optimized low‑level routines (Fortran/C) and supports parallel execution via mpi4py for efficient covariance estimation. Users can run provided scripts or integrate the library into their pipelines to generate covariance matrices, bias corrections, and related derivatives for cosmological analysis.