diff --git a/src/components/encounters/effects/AddEffectModal.tsx b/src/components/encounters/effects/AddEffectModal.tsx
index 6b4c2219..59a936fd 100644
--- a/src/components/encounters/effects/AddEffectModal.tsx
+++ b/src/components/encounters/effects/AddEffectModal.tsx
@@ -11,6 +11,7 @@ import {
   Stack,
   Box,
   IconButton,
+  Typography,
 } from "@mui/material"
 import CircleIcon from "@mui/icons-material/Circle"
 import { useState } from "react"
@@ -49,6 +50,8 @@ export default function AddEffectModal({
     change: "",
     character_id: character.id,
     shot_id: character.shot_id,
+    end_sequence: null,
+    end_shot: null,
   })
 
   // Define available action values based on character type
@@ -72,10 +75,19 @@ export default function AddEffectModal({
   const handleChange =
     (field: keyof CharacterEffect) =>
     (event: React.ChangeEvent<HTMLInputElement>) => {
-      setEffect(prev => ({
-        ...prev,
-        [field]: event.target.value,
-      }))
+      const value = event.target.value
+      // Handle numeric fields that can be null
+      if (field === "end_sequence" || field === "end_shot") {
+        setEffect(prev => ({
+          ...prev,
+          [field]: value === "" ? null : Number(value),
+        }))
+      } else {
+        setEffect(prev => ({
+          ...prev,
+          [field]: value,
+        }))
+      }
     }
 
   const handleSubmit = async () => {
@@ -113,6 +125,8 @@ export default function AddEffectModal({
       change: "",
       character_id: character.id,
       shot_id: character.shot_id,
+      end_sequence: null,
+      end_shot: null,
     })
     onClose()
   }
@@ -212,6 +226,38 @@ export default function AddEffectModal({
               />
             </Stack>
           </Box>
+
+          <Box>
+            <Box sx={{ mb: 1 }}>
+              <strong>Expiry (Optional)</strong>
+            </Box>
+            <Typography variant="body2" color="text.secondary" sx={{ mb: 1 }}>
+              Leave empty for permanent effect. Effect expires when the shot
+              counter passes the specified shot.
+            </Typography>
+            <Stack direction="row" spacing={2}>
+              <TextField
+                type="number"
+                label="Expires on Sequence"
+                name="end_sequence"
+                value={effect.end_sequence ?? ""}
+                onChange={handleChange("end_sequence")}
+                fullWidth
+                inputProps={{ min: 1 }}
+                helperText="Sequence number (1, 2, 3...)"
+              />
+              <TextField
+                type="number"
+                label="Expires on Shot"
+                name="end_shot"
+                value={effect.end_shot ?? ""}
+                onChange={handleChange("end_shot")}
+                fullWidth
+                inputProps={{ min: 0, max: 30 }}
+                helperText="Shot value (0-30)"
+              />
+            </Stack>
+          </Box>
         </Stack>
       </DialogContent>
       <DialogActions>
diff --git a/src/components/encounters/effects/CharacterEffectsDisplay.tsx b/src/components/encounters/effects/CharacterEffectsDisplay.tsx
index 564c047d..dc765816 100644
--- a/src/components/encounters/effects/CharacterEffectsDisplay.tsx
+++ b/src/components/encounters/effects/CharacterEffectsDisplay.tsx
@@ -145,6 +145,21 @@ export default function CharacterEffectsDisplay({
     return `${actionValueLabel(effect)} = ${effect.change}`
   }
 
+  const formatExpiry = (effect: CharacterEffect) => {
+    if (effect.end_sequence == null && effect.end_shot == null) {
+      return null
+    }
+
+    const parts: string[] = []
+    if (effect.end_sequence != null) {
+      parts.push(`Seq ${effect.end_sequence}`)
+    }
+    if (effect.end_shot != null) {
+      parts.push(`Shot ${effect.end_shot}`)
+    }
+    return `Expires: ${parts.join(", ")}`
+  }
+
   const severityOrder: Severity[] = ["error", "warning", "info", "success"]
 
   // Cleanup timeouts on unmount
@@ -219,50 +234,62 @@ export default function CharacterEffectsDisplay({
             onMouseEnter={handlePopoverMouseEnter}
             onMouseLeave={handlePopoverClose}
           >
-            {groupedEffects[openSeverity].map((effect, index) => (
-              <Stack
-                key={effect.id || index}
-                direction="row"
-                alignItems="center"
-                spacing={1}
-                sx={{
-                  py: 0.5,
-                  borderBottom:
-                    index < groupedEffects[openSeverity].length - 1
-                      ? "1px solid"
-                      : "none",
-                  borderColor: "divider",
-                }}
-              >
-                <InfoOutlinedIcon
-                  fontSize="small"
-                  color={severityColors[openSeverity]}
-                />
-                <Box sx={{ flex: 1 }}>
-                  <Typography variant="body2">
-                    {effect.name}
-                    {effect.action_value && effect.change && (
+            {groupedEffects[openSeverity].map((effect, index) => {
+              const expiry = formatExpiry(effect)
+              return (
+                <Stack
+                  key={effect.id || index}
+                  direction="row"
+                  alignItems="center"
+                  spacing={1}
+                  sx={{
+                    py: 0.5,
+                    borderBottom:
+                      index < groupedEffects[openSeverity].length - 1
+                        ? "1px solid"
+                        : "none",
+                    borderColor: "divider",
+                  }}
+                >
+                  <InfoOutlinedIcon
+                    fontSize="small"
+                    color={severityColors[openSeverity]}
+                  />
+                  <Box sx={{ flex: 1 }}>
+                    <Typography variant="body2">
+                      {effect.name}
+                      {effect.action_value && effect.change && (
+                        <Typography
+                          component="span"
+                          variant="body2"
+                          sx={{ ml: 1, fontWeight: "bold" }}
+                        >
+                          ({formatChange(effect)})
+                        </Typography>
+                      )}
+                    </Typography>
+                    {expiry && (
                       <Typography
-                        component="span"
-                        variant="body2"
-                        sx={{ ml: 1, fontWeight: "bold" }}
+                        variant="caption"
+                        color="text.secondary"
+                        sx={{ display: "block" }}
                       >
-                        ({formatChange(effect)})
+                        {expiry}
                       </Typography>
                     )}
-                  </Typography>
-                </Box>
-                {isGamemaster && (
-                  <IconButton
-                    size="small"
-                    onClick={() => handleDeleteEffect(effect)}
-                    sx={{ padding: 0.25 }}
-                  >
-                    <DeleteIcon sx={{ fontSize: 16 }} />
-                  </IconButton>
-                )}
-              </Stack>
-            ))}
+                  </Box>
+                  {isGamemaster && (
+                    <IconButton
+                      size="small"
+                      onClick={() => handleDeleteEffect(effect)}
+                      sx={{ padding: 0.25 }}
+                    >
+                      <DeleteIcon sx={{ fontSize: 16 }} />
+                    </IconButton>
+                  )}
+                </Stack>
+              )
+            })}
           </Box>
         )}
       </Popover>
diff --git a/src/types/resources.ts b/src/types/resources.ts
index c4920a42..1954600c 100644
--- a/src/types/resources.ts
+++ b/src/types/resources.ts
@@ -443,6 +443,8 @@ export interface CharacterEffect {
   change?: string
   action_value?: string
   shot_id: string
+  end_sequence?: number | null
+  end_shot?: number | null
 }
 
 export interface CharacterEffects {