Aim: The aim of this study is to present the clinical and histopathological features as well as the treatment results of advanced conjunctival malignant tumors with orbital invasion, in the context of all secondary orbital tumors. Methods: A total of 151 secondary orbital tumors were observed over a 10-year period; 21 (14%) out of 151 cases were detected to be of conjunctival origin, and the cases were reviewed retrospectively. The age, gender, duration of symptoms, clinical and histopathological features and the treatment results of patients were recorded. Results: Four out of 21 patients had malignant melanoma (MM), while 17 had squamous cell carcinoma (SCC) of the conjunctiva. The mean duration of symptoms was 11.3 months in the MM and 18.5 months in the SCC group. Perineural invasion was detected in 1 of the MM and 3 of the SCC cases. The peritumorous inflammation score was higher in the SCC than the MM group (2.2 vs. 1.5). Two patients underwent wide excision with control of the surgical margins and postoperative adjunctive topical chemotherapy. Nineteen patients needed exenteration. Two patients with regional metastasis were treated by radical neck dissection and radiation therapy to the neck. After a mean follow-up time of 35.6 months, no tumor recurrence or tumor-related death was encountered. Seven patients died from non-tumor-related causes. Conclusion: Delay in presentationfor treatment and previous unsuccessful surgery of conjunctival malignant lesions are likely to lead to orbital invasion and loss of the eye. Exenteration is generally needed but margin-controlled wide surgical excision and adjuvant chemotherapy may be curative in selected cases. Early diagnosis and effective treatment of lesions will minimize the mortality rate and morbidity related to the disease.