Small cyclic peptides (~15 residues or less) are appealing candidates for next generation drug development. With molecular weights larger than traditional small molecules but smaller than biologics (e.g. antibodies), such molecules are large enough to inhibit protein-protein interactions but can exhibit small molecule-like pharmacokinetics and oral availability. Moreover, rapid discovery systems (e.g. mRNA display) have become well established in recent years, making the identification of cyclic peptide ligands to disease-related proteins of interest relatively straightforward. However, the molecules discovered using such approaches usually exhibit molecular weights >1,200 Da, negatively affecting their pharmacokinetic properties (including oral availability) and greatly complicating clinical development. To address this shortcoming, we performed mRNA display with peptide libraries of restricted size, using a bromodomain and extra terminal (BET) protein family member - BRD3-BD1- as a model target. Eight cyclic peptide BRD3-BD1 ligands with molecular weights ranging from 1000 Da to 1300 Da (average mass) were identified and demonstrated to exhibit nanomolar to picomolar binding affinities for BRD3-BD1 by surface plasmon resonance. X-ray crystallography was then used to characterize the molecules and their binding modes. These findings demonstrate that reduced molecular weight cyclic peptide libraries can be used for mRNA display screening in order to identify molecules with potential for pharmaceutical development and delineate the mechanisms through which these molecules interact with their target.