To cope with constantly changing environments, plants employ versatile mechanisms. Gibberellins(GAs) are a class of well-characterized plant hormones that enable plastic growth and developments in higher plants throughout their life cycles. Several key components of GA metabolism and signaling have now been revealed through elegant molecular genetics analyses powered by genomics information from Arabidopsis and rice. Here, we highlight recent findings concerning the molecular mechanisms by which plants control their bioactive GA levels and sense/respond to changes in gibberellin concentrations.