T helper (TH) cells orchestrate appropriate cellular and humoral immune responses to a wide variety of pathogens and are central to the success of vaccines. However, their dysregulation can cause allergies and autoimmune diseases. The TH cell universe is characterized by a diversity of distinct cell types, such as TH1, TH2, TH17 cells, regulatory T cells, and T follicular helper cells, each featuring specific functions and gene expression programs, but also by plasticity among the different TH cell subsets. Here, we review recent advances and emerging concepts on how microRNAs, small endogenously expressed oligonucleotides that modulate gene expression, fit into the regulatory networks that govern T helper cell fate decisions and regulate their effector functions.