diff --git a/packages/opencode/src/cli/cmd/run/theme.ts b/packages/opencode/src/cli/cmd/run/theme.ts
index e4fb315426fa..76dda0b63c33 100644
--- a/packages/opencode/src/cli/cmd/run/theme.ts
+++ b/packages/opencode/src/cli/cmd/run/theme.ts
@@ -68,7 +68,7 @@ export type RunTheme = {
   block: RunBlockTheme
 }
 
-type ThemeColor = Exclude<keyof TuiThemeCurrent, "thinkingOpacity">
+type ThemeColor = Exclude<keyof TuiThemeCurrent, "thinkingOpacity" | "_hasSelectedListItemText" | "transparent">
 type HexColor = `#${string}`
 type RefName = string
 type Variant = {
@@ -87,6 +87,7 @@ type ThemeJson = {
 
 type SharedSyntaxTheme = TuiThemeCurrent & {
   _hasSelectedListItemText: boolean
+  transparent: boolean
 }
 
 export const transparent = RGBA.fromValues(0, 0, 0, 0)
@@ -675,6 +676,7 @@ export async function resolveRunTheme(renderer: CliRenderer): Promise<RunTheme>
     const syntaxTheme: SharedSyntaxTheme = {
       ...scrollbackTheme,
       _hasSelectedListItemText: true,
+      transparent: false,
     }
     const syntax = shared.generateSyntax(syntaxTheme)
     return map(
diff --git a/packages/tui/src/app.tsx b/packages/tui/src/app.tsx
index 17a9a554c2e4..eeda29501c63 100644
--- a/packages/tui/src/app.tsx
+++ b/packages/tui/src/app.tsx
@@ -116,6 +116,7 @@ const appBindingCommands = [
   "theme.switch",
   "theme.switch_mode",
   "theme.mode.lock",
+  "theme.transparency",
   "help.show",
   "docs.open",
   "workspace.list",
@@ -362,7 +363,7 @@ function App(props: { onSnapshot?: () => Promise<string[]>; pluginHost: TuiPlugi
   const sdk = useSDK()
   const toast = useToast()
   const themeState = useTheme()
-  const { theme, mode, setMode, locked, lock, unlock } = themeState
+  const { theme, mode, setMode, locked, lock, unlock, transparency, setTransparency } = themeState
   const sync = useSync()
   const project = useProject()
   const exit = useExit()
@@ -783,6 +784,17 @@ function App(props: { onSnapshot?: () => Promise<string[]>; pluginHost: TuiPlugi
         },
         category: "System",
       },
+      {
+        name: "theme.transparency",
+        title: `Transparency: ${
+          transparency() === "auto" ? `Auto (${theme.transparent ? "on" : "off"})` : transparency() === "on" ? "Force on" : "Force off"
+        }`,
+        run: () => {
+          setTransparency(transparency() === "auto" ? "on" : transparency() === "on" ? "off" : "auto")
+          dialog.clear()
+        },
+        category: "System",
+      },
       {
         name: "help.show",
         title: "Help",
diff --git a/packages/tui/src/config/keybind.ts b/packages/tui/src/config/keybind.ts
index 0028b610f2a3..68950ff112c1 100644
--- a/packages/tui/src/config/keybind.ts
+++ b/packages/tui/src/config/keybind.ts
@@ -77,6 +77,7 @@ export const Definitions = {
   theme_list: keybind("<leader>t", "List available themes"),
   theme_switch_mode: keybind("none", "Switch between light and dark theme mode"),
   theme_mode_lock: keybind("none", "Lock or unlock theme mode"),
+  theme_transparency: keybind("none", "Cycle theme transparency policy"),
   sidebar_toggle: keybind("<leader>b", "Toggle sidebar"),
   scrollbar_toggle: keybind("none", "Toggle session scrollbar"),
   status_view: keybind("<leader>s", "View status"),
@@ -282,6 +283,7 @@ export const CommandMap = {
   theme_list: "theme.switch",
   theme_switch_mode: "theme.switch_mode",
   theme_mode_lock: "theme.mode.lock",
+  theme_transparency: "theme.transparency",
   sidebar_toggle: "session.sidebar.toggle",
   scrollbar_toggle: "session.toggle.scrollbar",
   status_view: "opencode.status",
diff --git a/packages/tui/src/context/theme.tsx b/packages/tui/src/context/theme.tsx
index 909dd69ac249..d7ddf76841c7 100644
--- a/packages/tui/src/context/theme.tsx
+++ b/packages/tui/src/context/theme.tsx
@@ -17,6 +17,7 @@ import {
   terminalMode,
   tint,
   upsertTheme,
+  type ThemeTransparency,
   type ThemeJson,
 } from "../theme"
 import { createEffect, createMemo, onCleanup, onMount } from "solid-js"
@@ -77,6 +78,7 @@ export {
   type Theme,
   type ThemeJson,
   type SyntaxStyleOverrides,
+  type ThemeTransparency,
 } from "../theme"
 
 const THEME_REFRESH_DELAYS = [250, 1000] as const
@@ -86,6 +88,7 @@ type State = {
   mode: "dark" | "light"
   lock: "dark" | "light" | undefined
   active: string
+  transparency: ThemeTransparency
   ready: boolean
 }
 
@@ -94,6 +97,7 @@ const [store, setStore] = createStore<State>({
   mode: "dark",
   lock: undefined,
   active: "opencode",
+  transparency: "auto",
   ready: false,
 })
 
@@ -110,6 +114,10 @@ export const { use: useTheme, provider: ThemeProvider } = createSimpleContext({
       if (value === "dark" || value === "light") return value
       return
     }
+    const pickTransparency = (value: unknown): ThemeTransparency => {
+      if (value === "auto" || value === "on" || value === "off") return value
+      return value === true ? "on" : "auto"
+    }
 
     setStore(
       produce((draft) => {
@@ -120,6 +128,7 @@ export const { use: useTheme, provider: ThemeProvider } = createSimpleContext({
         draft.lock = lock
         const active = config.theme ?? kv.get("theme", "opencode")
         draft.active = typeof active === "string" ? active : "opencode"
+        draft.transparency = pickTransparency(kv.get("theme_transparent", "auto"))
         draft.ready = false
       }),
     )
@@ -255,15 +264,15 @@ export const { use: useTheme, provider: ThemeProvider } = createSimpleContext({
 
     const values = createMemo(() => {
       const active = store.themes[store.active]
-      if (active) return resolveTheme(active, store.mode)
+      if (active) return resolveTheme(active, store.mode, store.transparency)
 
       const saved = kv.get("theme")
       if (typeof saved === "string") {
         const theme = store.themes[saved]
-        if (theme) return resolveTheme(theme, store.mode)
+        if (theme) return resolveTheme(theme, store.mode, store.transparency)
       }
 
-      return resolveTheme(store.themes.opencode, store.mode)
+      return resolveTheme(store.themes.opencode, store.mode, store.transparency)
     })
 
     createEffect(() => renderer.setBackgroundColor(values().background))
@@ -296,6 +305,13 @@ export const { use: useTheme, provider: ThemeProvider } = createSimpleContext({
         kv.set("theme", theme)
         return true
       },
+      transparency() {
+        return store.transparency
+      },
+      setTransparency(transparency: ThemeTransparency) {
+        setStore("transparency", transparency)
+        kv.set("theme_transparent", transparency)
+      },
       get ready() {
         return store.ready
       },
diff --git a/packages/tui/src/theme/index.ts b/packages/tui/src/theme/index.ts
index e8a5f2c5a973..412c3b943683 100644
--- a/packages/tui/src/theme/index.ts
+++ b/packages/tui/src/theme/index.ts
@@ -88,8 +88,10 @@ export type Theme = {
   readonly syntaxPunctuation: RGBA
   readonly thinkingOpacity: number
   _hasSelectedListItemText: boolean
+  transparent: boolean
 }
-type ThemeColor = Exclude<keyof Theme, "thinkingOpacity" | "_hasSelectedListItemText">
+export type ThemeTransparency = "auto" | "on" | "off"
+type ThemeColor = Exclude<keyof Theme, "thinkingOpacity" | "_hasSelectedListItemText" | "transparent">
 export type SyntaxStyleOverrides = Record<string, { italic?: boolean }>
 
 export function selectedForeground(theme: Theme, bg?: RGBA): RGBA {
@@ -157,8 +159,8 @@ export const DEFAULT_THEMES: Record<string, ThemeJson> = {
   solarized,
   synthwave84,
   tokyonight,
-  vesper,
   vercel,
+  vesper,
   zenburn,
   carbonfox,
 }
@@ -238,7 +240,7 @@ export function upsertTheme(name: string, theme: unknown) {
   return true
 }
 
-export function resolveTheme(theme: ThemeJson, mode: "dark" | "light") {
+export function resolveTheme(theme: ThemeJson, mode: "dark" | "light", transparency: ThemeTransparency = "auto") {
   const defs = theme.defs ?? {}
   function resolveColor(c: ColorValue, chain: string[] = []): RGBA {
     if (c instanceof RGBA) return c
@@ -291,10 +293,18 @@ export function resolveTheme(theme: ThemeJson, mode: "dark" | "light") {
   // Handle thinkingOpacity - optional with default of 0.6
   const thinkingOpacity = theme.theme.thinkingOpacity ?? 0.6
 
+  if (transparency === "on" && resolved.background) {
+    resolved.background = RGBA.fromValues(resolved.background.r, resolved.background.g, resolved.background.b, 0)
+  }
+  if (transparency === "off" && resolved.background && resolved.background.a < 1) {
+    resolved.background = RGBA.fromValues(resolved.background.r, resolved.background.g, resolved.background.b, 1)
+  }
+
   return {
     ...resolved,
     _hasSelectedListItemText: hasSelectedListItemText,
     thinkingOpacity,
+    transparent: resolved.background !== undefined && resolved.background.a < 1,
   } as Theme
 }
 
diff --git a/packages/tui/test/theme.test.ts b/packages/tui/test/theme.test.ts
index acdb2a39c41e..bc7ca070b612 100644
--- a/packages/tui/test/theme.test.ts
+++ b/packages/tui/test/theme.test.ts
@@ -1,8 +1,8 @@
 import { expect, test } from "bun:test"
 import { mkdir, writeFile } from "node:fs/promises"
 import path from "node:path"
-import type { TerminalColors } from "@opentui/core"
-import { DEFAULT_THEMES, addTheme, allThemes, hasTheme, resolveTheme, terminalMode } from "../src/theme"
+import { RGBA, type TerminalColors } from "@opentui/core"
+import { DEFAULT_THEMES, addTheme, allThemes, generateSystem, hasTheme, resolveTheme, terminalMode } from "../src/theme"
 import { discoverThemes } from "../src/context/theme"
 import { tmpdir } from "./fixture/fixture"
 
@@ -44,6 +44,43 @@ test("resolveTheme rejects circular color refs", () => {
   expect(() => resolveTheme(item, "dark")).toThrow("Circular color reference")
 })
 
+test("resolveTheme transparency policy respects auto, on, and off", () => {
+  const base = resolveTheme(DEFAULT_THEMES.opencode, "dark", "auto")
+  const forced = resolveTheme(DEFAULT_THEMES.opencode, "dark", "on")
+
+  expect(base.background.a).toBe(1)
+  expect(forced.background.a).toBe(0)
+  expect(forced.background.r).toBe(base.background.r)
+  expect(forced.background.g).toBe(base.background.g)
+  expect(forced.background.b).toBe(base.background.b)
+  expect(forced.transparent).toBe(true)
+
+  const palette = Array.from({ length: 16 }, () => "#1a1b26")
+  palette[7] = "#c0caf5"
+
+  const system = generateSystem(terminalColors("#1a1b26", palette), "dark")
+  const automatic = resolveTheme(system, "dark", "auto")
+  const disabled = resolveTheme(system, "dark", "off")
+
+  expect(automatic.background.a).toBe(0)
+  expect(automatic.transparent).toBe(true)
+  expect(disabled.background.a).toBe(1)
+  expect(disabled.background.r).toBe(automatic.background.r)
+  expect(disabled.background.g).toBe(automatic.background.g)
+  expect(disabled.background.b).toBe(automatic.background.b)
+  expect(disabled.transparent).toBe(false)
+
+  const partial = structuredClone(DEFAULT_THEMES.opencode)
+  partial.theme.background = RGBA.fromValues(base.background.r, base.background.g, base.background.b, 0.5)
+  const automaticPartial = resolveTheme(partial, "dark", "auto")
+  const disabledPartial = resolveTheme(partial, "dark", "off")
+
+  expect(automaticPartial.background.a).toBeCloseTo(0.5)
+  expect(automaticPartial.transparent).toBe(true)
+  expect(disabledPartial.background.a).toBe(1)
+  expect(disabledPartial.transparent).toBe(false)
+})
+
 function terminalColors(defaultBackground: string | null, palette: Array<string | null> = []): TerminalColors {
   return {
     palette,