diff --git a/orbit/changes/46461-orbit-boottime-cache b/orbit/changes/46461-orbit-boottime-cache
new file mode 100644
index 0000000000..ca49695ed5
--- /dev/null
+++ b/orbit/changes/46461-orbit-boottime-cache
@@ -0,0 +1 @@
+- Fixed orbit repeatedly reading `/proc/stat` (and `/proc/uptime` on containerized hosts) once per running process every time it enumerated the process table (for example, the Fleet Desktop watchdog that polls every 15s). Orbit now caches the system boot time, eliminating the redundant reads.
diff --git a/orbit/pkg/platform/platform_linux.go b/orbit/pkg/platform/platform_linux.go
new file mode 100644
index 0000000000..b670fb9120
--- /dev/null
+++ b/orbit/pkg/platform/platform_linux.go
@@ -0,0 +1,35 @@
+//go:build linux
+
+package platform
+
+import (
+	gopsutil_process "github.com/shirou/gopsutil/v4/process"
+)
+
+func init() {
+	// Enable gopsutil's boot-time cache (Linux only).
+	//
+	// gopsutil_process.Processes() builds a Process for every PID, and the
+	// constructor (NewProcess -> CreateTime -> fillFromStat) computes each
+	// process' creation time, which requires the system boot time. By default
+	// gopsutil does NOT cache the boot time, so on Linux it re-reads /proc/stat
+	// (or /proc/uptime on containerized hosts) once per process, on every call.
+	//
+	// orbit enumerates the full process table on a recurring basis (e.g. the
+	// Fleet Desktop watchdog polls every 15s via GetProcessesByName), so this
+	// caused the host-wide /proc/stat file to be read N times per poll, where N
+	// is the total number of running processes. The btime field lives near the
+	// end of /proc/stat, so each read scans the entire file just to recover a
+	// single constant value.
+	//
+	// The system boot time does not change for the lifetime of the orbit
+	// process, so caching it is safe and collapses those repeated reads into a
+	// single one. This is scoped to Linux because that is where the redundant
+	// file reads occur; macOS and Windows obtain boot time via syscall/sysctl.
+	//
+	// Note: orbit only reads process Name/Pid and never a process' CreateTime,
+	// so the cache cannot surface a stale value (the gopsutil README warns that
+	// a cached boot time can drift if NTP steps the clock after boot, which only
+	// affects CreateTime).
+	gopsutil_process.EnableBootTimeCache(true)
+}