The government declared a state of emergency after an Islamic State affiliate bombed two Coptic churches in April 2017, killing at least 44 people, and it has been renewed once before.
President Abdel-Fattah el-Sissi's latest renewal was published in the official gazette on Tuesday.
Parliament is expected to approve it within seven days, and it has already taken effect.
Egypt has been battling Islamic militants for years, mainly in the restive northern Sinai, but the insurgency gained strength after the 2013 overthrow of an elected but divisive Islamist president.
The militants have mainly targeted security forces and Christians.
In February, Egypt launched a massive nationwide security operation.
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