Lectures on Geophysical Fluid Dynamics offers an introduction to several topics in theoretical geophysical fluid dynamics, including the theory of large-scale ocean circulation, geostrophic turbulence, and Hamiltonian fluid dynamics. The book is based on an introductory course in dynamical oceanography offered to first-year graduate students at Scripps Institution of Oceanography. Each chapter is a self-contained introduction to its particular subject. Overall, the emphasis througout the book is on physical ideas rather than mathematical techniques. Readers are assumed to have had an elementary introduction to fluid dynamics, to know advanced calculus through partial differential equations, and to be familiar with the elementary ideas about linear waves, including the concept of group velocity.