diff --git a/esphome/components/zephyr/__init__.py b/esphome/components/zephyr/__init__.py
index b8a091feb92..348e7a3cf2d 100644
--- a/esphome/components/zephyr/__init__.py
+++ b/esphome/components/zephyr/__init__.py
@@ -122,6 +122,8 @@ def zephyr_to_code(config: ConfigType) -> None:
     zephyr_add_prj_conf("FPU", True)
     zephyr_add_prj_conf("NEWLIB_LIBC_FLOAT_PRINTF", True)
     zephyr_add_prj_conf("STD_CPP20", True)
+    # random_bytes() uses sys_rand_get() which requires the entropy subsystem
+    zephyr_add_prj_conf("ENTROPY_GENERATOR", True)
 
     # <err> os: ***** USAGE FAULT *****
     # <err> os:   Illegal load of EXC_RETURN into PC