diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0dc65033..46b1410e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 - [#62](https://github.com/thanos-io/objstore/pull/62) S3: Fix ignored context cancellation in `Iter` method.
 - [#77](https://github.com/thanos-io/objstore/pull/77) Fix buckets wrapped with metrics from being unable to determine object sizes in `Upload`.
 - [#78](https://github.com/thanos-io/objstore/pull/78) S3: Fix possible concurrent modification of the PutUserMetadata map.
+- [#79](https://github.com/thanos-io/objstore/pull/79) Metrics: Fix `objstore_bucket_operation_duration_seconds` for `iter` operations.
 
 ### Added
 - [#15](https://github.com/thanos-io/objstore/pull/15) Add Oracle Cloud Infrastructure Object Storage Bucket support.
diff --git a/go.mod b/go.mod
index dee14caa..d66fc2fe 100644
--- a/go.mod
+++ b/go.mod
@@ -27,6 +27,7 @@ require (
 	golang.org/x/oauth2 v0.4.0
 	golang.org/x/sync v0.1.0
 	google.golang.org/api v0.103.0
+	google.golang.org/grpc v1.53.0
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 	gopkg.in/yaml.v2 v2.4.0
 )
@@ -92,7 +93,6 @@ require (
 	golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 // indirect
 	google.golang.org/appengine v1.6.7 // indirect
 	google.golang.org/genproto v0.0.0-20230110181048-76db0878b65f // indirect
-	google.golang.org/grpc v1.53.0 // indirect
 	google.golang.org/protobuf v1.28.1 // indirect
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
diff --git a/go.sum b/go.sum
index 860aca72..45756f80 100644
--- a/go.sum
+++ b/go.sum
@@ -491,7 +491,6 @@ golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20210616045830-e2b7044e8c71/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211216021012-1d35b9e2eb4e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220114195835-da31bd327af9/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
diff --git a/objstore.go b/objstore.go
index 20723704..219a9572 100644
--- a/objstore.go
+++ b/objstore.go
@@ -433,7 +433,7 @@ func WrapWithMetrics(b Bucket, reg prometheus.Registerer, name string) *metricBu
 
 		opsDuration: promauto.With(reg).NewHistogramVec(prometheus.HistogramOpts{
 			Name:        "objstore_bucket_operation_duration_seconds",
-			Help:        "Duration of successful operations against the bucket",
+			Help:        "Duration of successful operations against the bucket per operation - iter operations include time spent on each callback.",
 			ConstLabels: prometheus.Labels{"bucket": name},
 			Buckets:     []float64{0.001, 0.01, 0.1, 0.3, 0.6, 1, 3, 6, 9, 20, 30, 60, 90, 120},
 		}, []string{"operation"}),
@@ -504,12 +504,14 @@ func (b *metricBucket) Iter(ctx context.Context, dir string, f func(name string)
 	const op = OpIter
 	b.ops.WithLabelValues(op).Inc()
 
+	start := time.Now()
 	err := b.bkt.Iter(ctx, dir, f, options...)
 	if err != nil {
 		if !b.isOpFailureExpected(err) && ctx.Err() != context.Canceled {
 			b.opsFailures.WithLabelValues(op).Inc()
 		}
 	}
+	b.opsDuration.WithLabelValues(op).Observe(time.Since(start).Seconds())
 	return err
 }