diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3a213fe6cf1..330e197e129 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 ### 💡 Enhancements 💡
 
 - Add `linux-ppc64le` architecture to cross build tests in CI
+- `client`: perform case insensitive lookups in case the requested metadata value isn't found (#5646)
 
 ### 🧰 Bug fixes 🧰
 
diff --git a/client/client.go b/client/client.go
index b5974e53a06..4b3f701badb 100644
--- a/client/client.go
+++ b/client/client.go
@@ -91,6 +91,7 @@ package client // import "go.opentelemetry.io/collector/client"
 import (
 	"context"
 	"net"
+	"strings"
 )
 
 type ctxKey struct{}
@@ -160,7 +161,19 @@ func NewMetadata(md map[string][]string) Metadata {
 func (m Metadata) Get(key string) []string {
 	vals := m.data[key]
 	if len(vals) == 0 {
-		return nil
+		// we didn't find the key, but perhaps it just has different cases?
+		for k, v := range m.data {
+			if strings.EqualFold(key, k) {
+				vals = v
+				// we optimize for the next lookup
+				m.data[key] = v
+			}
+		}
+
+		// if it's still not found, it's really not here
+		if len(vals) == 0 {
+			return nil
+		}
 	}
 
 	ret := make([]string, len(vals))
diff --git a/client/client_test.go b/client/client_test.go
index 3249e84e905..a43fecc7e0b 100644
--- a/client/client_test.go
+++ b/client/client_test.go
@@ -91,6 +91,7 @@ func TestMetadata(t *testing.T) {
 	source := map[string][]string{"test-key": {"test-val"}}
 	md := NewMetadata(source)
 	assert.Equal(t, []string{"test-val"}, md.Get("test-key"))
+	assert.Equal(t, []string{"test-val"}, md.Get("test-KEY")) // case insensitive lookup
 
 	// test if copy. In regular use, source cannot change
 	val := md.Get("test-key")