diff --git a/internal/httpapi/handlers_calendar.go b/internal/httpapi/handlers_calendar.go
index 91b38fe..ec8e72e 100644
--- a/internal/httpapi/handlers_calendar.go
+++ b/internal/httpapi/handlers_calendar.go
@@ -1,11 +1,13 @@
 package httpapi
 
 import (
+	"encoding/json"
 	"net/http"
 
 	"spin/internal/models"
 
 	"github.com/go-chi/chi/v5"
+	"gorm.io/datatypes"
 )
 
 // 개인 캘린더 — 각자 본인 이벤트만 보고 관리(분류: 프로젝트/기타/개인 + 색).
@@ -47,6 +49,11 @@ func (s *Server) handlePatchEvent(w http.ResponseWriter, r *http.Request) {
 	}
 	delete(patch, "id")
 	delete(patch, "ownerEmail")
+	if v, ok := patch["participants"]; ok {
+		if b, err := json.Marshal(v); err == nil {
+			patch["participants"] = datatypes.JSON(b)
+		}
+	}
 	s.db.Model(&e).Updates(snakeKeys(patch))
 	s.db.First(&e, "id = ?", e.ID)
 	writeJSON(w, http.StatusOK, e)
diff --git a/internal/models/project.go b/internal/models/project.go
index 19b8701..dd832c7 100644
--- a/internal/models/project.go
+++ b/internal/models/project.go
@@ -176,17 +176,18 @@ type ProjectMailState struct {
 // with a color. Owned by one member.
 type CalendarEvent struct {
 	Base
-	OwnerEmail string    `gorm:"index" json:"ownerEmail"`
-	Title      string    `json:"title"`
-	Category   string    `json:"category"`  // project | etc | personal (분류 키)
-	ProjectID  string    `json:"projectId"` // category=project일 때 연결
-	Color      string    `json:"color"`     // 표시 색
-	Start      string    `json:"start"`     // YYYY-MM-DD
-	End        string    `json:"end"`       // YYYY-MM-DD (빈값=하루)
-	AllDay     bool      `json:"allDay"`
-	Memo       string    `json:"memo"`
-	CreatedAt  time.Time `json:"createdAt"`
-	UpdatedAt  time.Time `json:"updatedAt"`
+	OwnerEmail   string                      `gorm:"index" json:"ownerEmail"`
+	Title        string                      `json:"title"`
+	Category     string                      `json:"category"`  // project | etc | personal (분류 키)
+	ProjectID    string                      `json:"projectId"` // category=project일 때 연결
+	Color        string                      `json:"color"`     // 표시 색
+	Start        string                      `json:"start"`     // YYYY-MM-DD
+	End          string                      `json:"end"`       // YYYY-MM-DD (빈값=하루)
+	AllDay       bool                        `json:"allDay"`
+	Memo         string                      `json:"memo"`
+	Participants datatypes.JSONSlice[string] `json:"participants"` // 참여자 이메일 — 그들 캘린더에도 표시
+	CreatedAt    time.Time                   `json:"createdAt"`
+	UpdatedAt    time.Time                   `json:"updatedAt"`
 }
 
 func (m *CalendarEvent) BeforeCreate(*gorm.DB) error { m.ensureID(); return nil }