This chapter is dedicated to the proof of comparison principles in general potential theories; that is, the proof that if a subharmonic-superharmonic pair for a subequation \(\mathcal F\) are ordered on the boundary of a bounded domain, then they are ordered in the interior of the domain. Two distinct situations will be presented. The first situation concerns the use of the monotonicity-duality method which works when \(\mathcal F\) has sufficient monotonicity. The second situation concerns the extreme case when \(\mathcal F\) has only the minimal monotonicity that any subequation must have. In this situation, a result on strict comparison is presented for semiconvex subharmonics and dual subharmonics.