diff --git a/internal/modules/master/phase-activities/controllers/phase-activity.controller.go b/internal/modules/master/phase-activities/controllers/phase-activity.controller.go
index 455ff1e4..3cbc68f2 100644
--- a/internal/modules/master/phase-activities/controllers/phase-activity.controller.go
+++ b/internal/modules/master/phase-activities/controllers/phase-activity.controller.go
@@ -28,20 +28,12 @@ func (u *PhaseActivityController) GetAll(c *fiber.Ctx) error {
 		Limit:  c.QueryInt("limit", 10),
 		Search: c.Query("search", ""),
 	}
+	query.PhaseIDs = c.Query("phase_ids", "")
 
 	if query.Page < 1 || query.Limit < 1 {
 		return fiber.NewError(fiber.StatusBadRequest, "page and limit must be greater than 0")
 	}
 
-	if phaseParam := c.Query("phase_id", ""); phaseParam != "" {
-		id, err := strconv.Atoi(phaseParam)
-		if err != nil || id <= 0 {
-			return fiber.NewError(fiber.StatusBadRequest, "invalid phase_id")
-		}
-		temp := uint(id)
-		query.PhaseId = &temp
-	}
-
 	result, totalResults, err := u.PhaseActivityService.GetAll(c, query)
 	if err != nil {
 		return err
diff --git a/internal/modules/master/phase-activities/services/phase-activity.service.go b/internal/modules/master/phase-activities/services/phase-activity.service.go
index 3cedb4fc..24b8272e 100644
--- a/internal/modules/master/phase-activities/services/phase-activity.service.go
+++ b/internal/modules/master/phase-activities/services/phase-activity.service.go
@@ -2,6 +2,7 @@ package service
 
 import (
 	"errors"
+	"strconv"
 	"strings"
 
 	entity "gitlab.com/mbugroup/lti-api.git/internal/entities"
@@ -57,8 +58,11 @@ func (s phaseActivityService) GetAll(c *fiber.Ctx, params *validation.Query) ([]
 		if params.Search != "" {
 			db = db.Where("name LIKE ?", "%"+params.Search+"%")
 		}
-		if params.PhaseId != nil {
-			db = db.Where("phase_id = ?", *params.PhaseId)
+		if params.PhaseIDs != "" {
+			ids := parseIDs(params.PhaseIDs)
+			if len(ids) > 0 {
+				db = db.Where("phase_id IN ?", ids)
+			}
 		}
 		return db.Order("created_at DESC").Order("updated_at DESC")
 	})
@@ -166,3 +170,18 @@ func (s phaseActivityService) DeleteOne(c *fiber.Ctx, id uint) error {
 	}
 	return nil
 }
+
+func parseIDs(raw string) []uint {
+	parts := strings.Split(raw, ",")
+	results := make([]uint, 0, len(parts))
+	for _, part := range parts {
+		value := strings.TrimSpace(part)
+		if value == "" {
+			continue
+		}
+		if n, err := strconv.ParseUint(value, 10, 64); err == nil {
+			results = append(results, uint(n))
+		}
+	}
+	return results
+}
diff --git a/internal/modules/master/phase-activities/validations/phase-activity.validation.go b/internal/modules/master/phase-activities/validations/phase-activity.validation.go
index a2ab8e1b..54186315 100644
--- a/internal/modules/master/phase-activities/validations/phase-activity.validation.go
+++ b/internal/modules/master/phase-activities/validations/phase-activity.validation.go
@@ -14,8 +14,8 @@ type Update struct {
 }
 
 type Query struct {
-	Page    int    `query:"page" validate:"omitempty,number,min=1,gt=0"`
-	Limit   int    `query:"limit" validate:"omitempty,number,min=1,max=100,gt=0"`
-	Search  string `query:"search" validate:"omitempty,max=50"`
-	PhaseId *uint  `query:"phase_id" validate:"omitempty"`
+	Page     int    `query:"page" validate:"omitempty,number,min=1,gt=0"`
+	Limit    int    `query:"limit" validate:"omitempty,number,min=1,max=100,gt=0"`
+	Search   string `query:"search" validate:"omitempty,max=50"`
+	PhaseIDs string `query:"phase_ids" validate:"omitempty"`
 }