diff --git a/CHANGELOG.md b/CHANGELOG.md
index f2a4e7f95c8..16bbbb2deb9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,8 @@ release.
 - Clarify the return of `Export(batch)` in the Batch Span Processor and exporter
   concurrency ([#2452](https://github.com/open-telemetry/opentelemetry-specification/pull/2452))
 - Clarify that Context should not be mutable when setting a span ([#2637](https://github.com/open-telemetry/opentelemetry-specification/pull/2637))
+- Clarify that `ForceFlush` is a required method on `SpanExporter` interface.
+  ([#2654](https://github.com/open-telemetry/opentelemetry-specification/pull/2654)).
 
 ### Metrics
 
diff --git a/specification/trace/sdk.md b/specification/trace/sdk.md
index e3f3a9570ee..edbcdf25573 100644
--- a/specification/trace/sdk.md
+++ b/specification/trace/sdk.md
@@ -602,8 +602,8 @@ primarily a simple telemetry data encoder and transmitter.
 
 ### Interface Definition
 
-The exporter must support two functions: **Export** and **Shutdown**. In
-strongly typed languages typically there will be 2 separate `Exporter`
+The exporter MUST support three functions: **Export**, **Shutdown**, and **ForceFlush**.
+In strongly typed languages typically there will be 2 separate `Exporter`
 interfaces, one that accepts spans (SpanExporter) and one that accepts metrics
 (MetricsExporter).