diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1a47d2b6451..da030b9193f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ### Fixed
 
 - The `go.opentelemetry.io/otel/exporters/prometheus` exporter fixes duplicated `_total` suffixes. (#3369)
+- Cumulative metrics from the OpenCensus bridge (`go.opentelemetry.io/otel/bridge/opencensus`) are defined as monotonic sums, instead of non-monotonic. (#3389)
 - Asynchronous counters (`Counter` and `UpDownCounter`) from the metric SDK now produce delta sums when configured with delta temporality. (#3398)
 
 ## [1.11.1/0.33.0] 2022-10-19
diff --git a/bridge/opencensus/internal/ocmetric/metric.go b/bridge/opencensus/internal/ocmetric/metric.go
index 575e99abe75..54b6619a1f6 100644
--- a/bridge/opencensus/internal/ocmetric/metric.go
+++ b/bridge/opencensus/internal/ocmetric/metric.go
@@ -92,7 +92,7 @@ func convertGauge[N int64 | float64](labelKeys []ocmetricdata.LabelKey, ts []*oc
 func convertSum[N int64 | float64](labelKeys []ocmetricdata.LabelKey, ts []*ocmetricdata.TimeSeries) (metricdata.Sum[N], error) {
 	points, err := convertNumberDataPoints[N](labelKeys, ts)
 	// OpenCensus sums are always Cumulative
-	return metricdata.Sum[N]{DataPoints: points, Temporality: metricdata.CumulativeTemporality}, err
+	return metricdata.Sum[N]{DataPoints: points, Temporality: metricdata.CumulativeTemporality, IsMonotonic: true}, err
 }
 
 // convertNumberDataPoints converts OpenCensus TimeSeries to OpenTelemetry DataPoints.
diff --git a/bridge/opencensus/internal/ocmetric/metric_test.go b/bridge/opencensus/internal/ocmetric/metric_test.go
index b93bc413088..19f74a6a887 100644
--- a/bridge/opencensus/internal/ocmetric/metric_test.go
+++ b/bridge/opencensus/internal/ocmetric/metric_test.go
@@ -312,6 +312,7 @@ func TestConvertMetrics(t *testing.T) {
 					Description: "an int testing sum",
 					Unit:        unit.Milliseconds,
 					Data: metricdata.Sum[int64]{
+						IsMonotonic: true,
 						Temporality: metricdata.CumulativeTemporality,
 						DataPoints: []metricdata.DataPoint[int64]{
 							{
@@ -342,6 +343,7 @@ func TestConvertMetrics(t *testing.T) {
 					Description: "a float testing sum",
 					Unit:        unit.Milliseconds,
 					Data: metricdata.Sum[float64]{
+						IsMonotonic: true,
 						Temporality: metricdata.CumulativeTemporality,
 						DataPoints: []metricdata.DataPoint[float64]{
 							{
@@ -410,6 +412,7 @@ func TestConvertMetrics(t *testing.T) {
 					Description: "a testing sum",
 					Unit:        unit.Dimensionless,
 					Data: metricdata.Sum[float64]{
+						IsMonotonic: true,
 						Temporality: metricdata.CumulativeTemporality,
 						DataPoints:  []metricdata.DataPoint[float64]{},
 					},