This study represents the first phytochemical analysis of <i>Stillingia loranthacea</i> (<i>S. loranthacea</i>) and describes new terpenoids obtained from the root bark of this species. The fractionation of the hexane extract from the root bark led to the isolation of two new 28-nor-taraxarenes derivatives, loranthones A and B (<b>1</b> and <b>2</b>), four new tigliane diterpenes (<b>5</b>-<b>8</b>), three known tigliane diterpenes (<b>9</b>-<b>11</b>), and three known flexibilene diterpenes, tonantzitlolones A-C (<b>12</b>-<b>14</b>). The investigation of these compounds and the use of a molecular networking-based prioritization approach afforded two other new 28-nor-taraxarenes, loranthones C and D (<b>3</b> and <b>4</b>). The cytotoxicity of compounds <b>1</b>, <b>2</b>, and <b>5</b>-<b>14</b> was evaluated against Vero cells, and their 20% cytotoxic concentration (CC<sub>20</sub>) values varied from 8.7 to 328 μM; antiviral activity was tested against an epidemic Zika virus (ZIKV) strain circulating in Brazil. Six out of 12 compounds (<b>2</b>, <b>5</b>, <b>9</b>-<b>11</b>, and <b>14</b>) exhibited significant antiviral effects against ZIKV. Specifically, compounds <b>2</b> and <b>5</b> offered the most promise as lead compounds as they had a 1.7 and 1.8 log<sub>10</sub> TCID<sub>50</sub>/mL reduction in ZIKV replication, respectively. Together, the present findings have identified <i>S. loranthacea</i> terpenoids as potent anti-ZIKV inhibitors and pave the way to the development of possible new treatments against this devastating pathogen.