This book was dedicated to the generalized fractional calculus of variations. We extended standard fractional variational calculus (Almeida et al. 2015;Malinowska and Torres 2012), by considering problems with generalized fractional operators, that by choosing special kernels reduce, e.g., to fractional operators of Riemann-Liouville, Caputo, Hadamard, Riesz, or Katugampola types.Keywords Generalized fractional operators · Generalized fractional calculus of variations · Directions for future research