Purpose: To explore the psychological problems (stress, depression, and anxiety) and the level of resilience among frontline healthcare workers (HCWs) who provide care for patients with coronavirus disease 2019 (COVID-19). Additionally, the current study identified the correlation among these problems, resilience, and demographics of participants. The study explored the main predictors of stress, depression, anxiety, and resilience. Methods: Both the descriptive cross-sectional correlational design and convenience sample technique were used to collect data from active Jordanian HCWs who directly deal with patients suspected or confirmed to be infected with COVID-19 and work at healthcare facilities in Jordan. Data were collected by using online questionnaires about the demographics, stress, anxiety, depression, and resilience of the participants. Results: Data were collected from 225 HCWs. Their mean age was 31.17 years (SD = 6.8). All the participants perceived different levels of stress, with most perceiving exposure to a high level of stress (distress) (46.2% with low level and 53.8% with high level of stress); approximately half of them (52.9%; n = 119) reported a high level of anxiety, and more than half (66.2%; n = 149) had a high level of depression. Additionally, an increased anxiety and depression level was significantly associated with the decreased resilience and increased stress level. Increased age and experience of HCWs are significantly correlated with increased stress levels. The participants having personal protection equipment (PPE) reduced anxiety and depression and increased resilience (p > 0.05). The predictors of the main variables were varied in the study. Conclusion: Frontline HCWs involved in treating the patients with COVID-19 are liable to have a high level of stress that is associated with increased anxiety and depression levels. These high levels affect their mental well-being and resilience. Healthcare institutions in Jordan must tailor appropriate psychological interventions and support that are congruent with the needs of HCWs during and after caring for patients with COVID-19.