diff --git a/workflow_step_execute.go b/workflow_step_execute.go
new file mode 100644
index 000000000..18516f23e
--- /dev/null
+++ b/workflow_step_execute.go
@@ -0,0 +1,85 @@
+package slack
+
+import (
+	"context"
+	"encoding/json"
+)
+
+type (
+	WorkflowStepCompletedRequest struct {
+		WorkflowStepExecuteID string            `json:"workflow_step_execute_id"`
+		Outputs               map[string]string `json:"outputs"`
+	}
+
+	WorkflowStepFailedRequest struct {
+		WorkflowStepExecuteID string `json:"workflow_step_execute_id"`
+		Error                 struct {
+			Message string `json:"message"`
+		} `json:"error"`
+	}
+)
+
+type WorkflowStepCompletedRequestOption func(opt WorkflowStepCompletedRequest) error
+
+func WorkflowStepCompletedRequestOptionOutput(outputs map[string]string) WorkflowStepCompletedRequestOption {
+	return func(opt WorkflowStepCompletedRequest) error {
+		if len(outputs) > 0 {
+			opt.Outputs = outputs
+		}
+		return nil
+	}
+}
+
+// WorkflowStepCompleted indicates step is completed
+func (api *Client) WorkflowStepCompleted(workflowStepExecuteID string, options ...WorkflowStepCompletedRequestOption) error {
+	// More information: https://api.slack.com/methods/workflows.stepCompleted
+	r := WorkflowStepCompletedRequest{
+		WorkflowStepExecuteID: workflowStepExecuteID,
+	}
+	for _, option := range options {
+		option(r)
+	}
+
+	endpoint := api.endpoint + "workflows.stepCompleted"
+	jsonData, err := json.Marshal(r)
+	if err != nil {
+		return err
+	}
+
+	response := &SlackResponse{}
+	if err := postJSON(context.Background(), api.httpclient, endpoint, api.token, jsonData, response, api); err != nil {
+		return err
+	}
+
+	if !response.Ok {
+		return response.Err()
+	}
+
+	return nil
+}
+
+// WorkflowStepFailed indicates step is failed
+func (api *Client) WorkflowStepFailed(workflowStepExecuteID string, errorMessage string) error {
+	// More information: https://api.slack.com/methods/workflows.stepFailed
+	r := WorkflowStepFailedRequest{
+		WorkflowStepExecuteID: workflowStepExecuteID,
+	}
+	r.Error.Message = errorMessage
+
+	endpoint := api.endpoint + "workflows.stepFailed"
+	jsonData, err := json.Marshal(r)
+	if err != nil {
+		return err
+	}
+
+	response := &SlackResponse{}
+	if err := postJSON(context.Background(), api.httpclient, endpoint, api.token, jsonData, response, api); err != nil {
+		return err
+	}
+
+	if !response.Ok {
+		return response.Err()
+	}
+
+	return nil
+}
diff --git a/workflow_step_execute_test.go b/workflow_step_execute_test.go
new file mode 100644
index 000000000..60c21c8ec
--- /dev/null
+++ b/workflow_step_execute_test.go
@@ -0,0 +1,35 @@
+package slack
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+)
+
+func workflowStepHandler(rw http.ResponseWriter, r *http.Request) {
+	rw.Header().Set("Content-Type", "application/json")
+	response, _ := json.Marshal(SlackResponse{
+		Ok: true,
+	})
+	rw.Write(response)
+}
+
+func TestWorkflowStepCompleted(t *testing.T) {
+	http.HandleFunc("/workflows.stepCompleted", workflowStepHandler)
+	once.Do(startServer)
+	api := New("testing-token", OptionAPIURL("http://"+serverAddr+"/"))
+
+	if err := api.WorkflowStepCompleted("executeID"); err != nil {
+		t.Errorf("Unexpected error: %s", err)
+	}
+}
+
+func TestWorkflowStepFailed(t *testing.T) {
+	http.HandleFunc("/workflows.stepFailed", workflowStepHandler)
+	once.Do(startServer)
+	api := New("testing-token", OptionAPIURL("http://"+serverAddr+"/"))
+
+	if err := api.WorkflowStepFailed("executeID", "error message"); err != nil {
+		t.Errorf("Unexpected error: %s", err)
+	}
+}