diff --git a/python/core/auto_generated/processing/qgsprocessingparameters.sip.in b/python/core/auto_generated/processing/qgsprocessingparameters.sip.in
index b2375c260dc4..da68d7b4ce9e 100644
--- a/python/core/auto_generated/processing/qgsprocessingparameters.sip.in
+++ b/python/core/auto_generated/processing/qgsprocessingparameters.sip.in
@@ -457,6 +457,44 @@ the dynamic parameter.
 .. seealso:: :py:func:`isDynamic`
 
 .. seealso:: :py:func:`setDynamicPropertyDefinition`
+%End
+
+    QStringList additionalExpressionContextVariables() const;
+%Docstring
+Returns a list of additional expression context variables which are available for use when evaluating
+this parameter.
+
+The additional variables will be added to the variables exposed from the usual expression
+context available to the parameter. They can be used to expose variables which are ONLY available
+to this parameter.
+
+The returned list should contain the variable names only, without the usual "@" prefix.
+
+.. seealso:: :py:func:`setAdditionalExpressionContextVariables`
+
+.. versionadded:: 3.8
+%End
+
+    void setAdditionalExpressionContextVariables( const QStringList &variables );
+%Docstring
+Sets a list of additional expression context ``variables`` which are available for use when evaluating
+this parameter.
+
+The additional variables will be added to the variables exposed from the usual expression
+context available to the parameter. They can be used to expose variables which are ONLY available
+to this parameter.
+
+The ``variables`` list should contain the variable names only, without the usual "@" prefix.
+
+.. note::
+
+   Specifying variables via this method is for metadata purposes only. It is the algorithm's responsibility
+   to correctly set the value of these additional variables in all expression context used when evaluating the parameter,
+   in whichever way is appropriate for that particular variable.
+
+.. seealso:: :py:func:`additionalExpressionContextVariables`
+
+.. versionadded:: 3.8
 %End
 
   protected:
@@ -471,6 +509,7 @@ the dynamic parameter.
 
 
 
+
 };
 
 QFlags<QgsProcessingParameterDefinition::Flag> operator|(QgsProcessingParameterDefinition::Flag f1, QFlags<QgsProcessingParameterDefinition::Flag> f2);
diff --git a/src/core/processing/qgsprocessingparameters.h b/src/core/processing/qgsprocessingparameters.h
index ef57db8dfd3f..19a4da884c88 100644
--- a/src/core/processing/qgsprocessingparameters.h
+++ b/src/core/processing/qgsprocessingparameters.h
@@ -515,6 +515,40 @@ class CORE_EXPORT QgsProcessingParameterDefinition
      */
     void setDynamicLayerParameterName( const QString &name ) { mDynamicLayerParameterName = name; }
 
+    /**
+     * Returns a list of additional expression context variables which are available for use when evaluating
+     * this parameter.
+     *
+     * The additional variables will be added to the variables exposed from the usual expression
+     * context available to the parameter. They can be used to expose variables which are ONLY available
+     * to this parameter.
+     *
+     * The returned list should contain the variable names only, without the usual "@" prefix.
+     *
+     * \see setAdditionalExpressionContextVariables()
+     * \since QGIS 3.8
+     */
+    QStringList additionalExpressionContextVariables() const { return mAdditionalExpressionVariables; }
+
+    /**
+     * Sets a list of additional expression context \a variables which are available for use when evaluating
+     * this parameter.
+     *
+     * The additional variables will be added to the variables exposed from the usual expression
+     * context available to the parameter. They can be used to expose variables which are ONLY available
+     * to this parameter.
+     *
+     * The \a variables list should contain the variable names only, without the usual "@" prefix.
+     *
+     * \note Specifying variables via this method is for metadata purposes only. It is the algorithm's responsibility
+     * to correctly set the value of these additional variables in all expression context used when evaluating the parameter,
+     * in whichever way is appropriate for that particular variable.
+     *
+     * \see additionalExpressionContextVariables()
+     * \since QGIS 3.8
+     */
+    void setAdditionalExpressionContextVariables( const QStringList &variables ) { mAdditionalExpressionVariables = variables; }
+
   protected:
 
     //! Parameter name
@@ -544,6 +578,9 @@ class CORE_EXPORT QgsProcessingParameterDefinition
     //! Linked vector layer parameter name for dynamic properties
     QString mDynamicLayerParameterName;
 
+    //! Additional expression context variables exposed for use by this parameter
+    QStringList mAdditionalExpressionVariables;
+
     // To allow access to mAlgorithm. We don't want a public setter for this!
     friend class QgsProcessingAlgorithm;
 
diff --git a/tests/src/analysis/testqgsprocessing.cpp b/tests/src/analysis/testqgsprocessing.cpp
index 34c9fdc95bad..721addac3cf6 100644
--- a/tests/src/analysis/testqgsprocessing.cpp
+++ b/tests/src/analysis/testqgsprocessing.cpp
@@ -1972,6 +1972,12 @@ void TestQgsProcessing::parameterGeneral()
   param.metadata().insert( "p3", 9 );
   QCOMPARE( param.metadata().value( "p3" ).toInt(), 9 );
 
+  QVERIFY( param.additionalExpressionContextVariables().isEmpty() );
+  param.setAdditionalExpressionContextVariables( QStringList() << "a" << "b" );
+  QCOMPARE( param.additionalExpressionContextVariables(), QStringList() << "a" << "b" );
+  std::unique_ptr< QgsProcessingParameterDefinition > param2( param.clone() );
+  QCOMPARE( param2->additionalExpressionContextVariables(), QStringList() << "a" << "b" );
+
   QVariantMap map = param.toVariantMap();
   QgsProcessingParameterBoolean fromMap( "x" );
   QVERIFY( fromMap.fromVariantMap( map ) );