Purpose This study compared predictors of passive suicidal ideation (SI), active SI, and suicide attempt (SA) among elderly Thai patients in tertiary care settings. Patients and Methods Psychiatric diagnoses and suicidality of 803 older people were assessed using the Mini-International Neuropsychiatric Interview and the Structured Clinical Interview for DSM-IV-TR. All participants completed the Montreal Cognitive Assessment, multidimensional scale of perceived social support (MSPSS), 15-item Thai geriatric depression scale (TGDS-15), 10-item perceived social scale and the Core Symptoms Index. The chi-square test, t -test and ANOVA were used for bivariate analysis of predictors of specific suicidality types. Multiple logistic regression was used to determine the predictors for each type of suicidality. Results The patients’ mean age was 69.24 ± 6.90 years, and the majority were female (69.74%). Passive SI, active SI and SA were found among 20.42%, 3.74% and 2.37%, respectively, of the patients. Major depressive disorder (MDD) was a predictor of both passive and active SI (OR = 2.06 and 3.74, respectively). Other predictors of passive SI included hypomania (OR = 8.27) and positive score on the TGDS-15 (OR = 1.29). Predictors of active SI included agoraphobia (OR = 6.84) and hypomania (OR = 7.10). Predictors of SA included a family history of alcohol dependence (OR = 14.16), a history of depression (OR = 4.78) and agoraphobia (OR = 19.89). Surprisingly, hypertension and self-reported anxiety symptoms were protective factors for passive SI (OR = 0.51 and 0.85, respectively). Likewise, MSPSS was a protective factor for SA (OR = 0.90). Conclusion Predictors of each type of suicidality differed. MDD was the main predictor for SI; however, agoraphobia and poor perceived social support were more pronounced among individuals with SA. Further investigation, especially in longitudinal fashion, should be warranted.