diff --git a/Cargo.lock b/Cargo.lock
index c7ddf6d..a08a4be 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1160,6 +1160,7 @@ dependencies = [
 name = "iamb"
 version = "0.0.4"
 dependencies = [
+ "bitflags",
  "chrono",
  "clap",
  "css-color-parser",
@@ -1172,6 +1173,7 @@ dependencies = [
  "mime",
  "mime_guess",
  "modalkit",
+ "open",
  "regex",
  "rpassword",
  "serde",
@@ -1765,6 +1767,16 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
 
+[[package]]
+name = "open"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2078c0039e6a54a0c42c28faa984e115fb4c2d5bf2208f77d1961002df8576f8"
+dependencies = [
+ "pathdiff",
+ "windows-sys",
+]
+
 [[package]]
 name = "os_str_bytes"
 version = "6.4.1"
@@ -1842,6 +1854,12 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "pathdiff"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8835116a5c179084a830efb3adc117ab007512b535bc1a21c991d3b32a6b44dd"
+
 [[package]]
 name = "pbkdf2"
 version = "0.11.0"
diff --git a/Cargo.toml b/Cargo.toml
index b9e0199..03a45a2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,6 +14,7 @@ categories = ["command-line-utilities"]
 rust-version = "1.66"
 
 [dependencies]
+bitflags = "1.3.2"
 chrono = "0.4"
 clap = {version = "4.0", features = ["derive"]}
 css-color-parser = "0.1.2"
@@ -23,6 +24,7 @@ html5ever = "0.26.0"
 markup5ever_rcdom = "0.2.0"
 mime = "^0.3.16"
 mime_guess = "^2.0.4"
+open = "3.2.0"
 regex = "^1.5"
 rpassword = "^7.2"
 serde = "^1.0"
diff --git a/src/base.rs b/src/base.rs
index ee74bb2..313728f 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -81,9 +81,9 @@ pub enum MessageAction {
 
     /// Download an attachment to the given path.
     ///
-    /// The [bool] argument controls whether to overwrite any already existing file at the
-    /// destination path.
-    Download(Option<String>, bool),
+    /// The second argument controls whether to overwrite any already existing file at the
+    /// destination path, or to open the attachment after downloading.
+    Download(Option<String>, DownloadFlags),
 
     /// Edit a sent message.
     Edit,
@@ -95,6 +95,18 @@ pub enum MessageAction {
     Reply,
 }
 
+bitflags::bitflags! {
+    pub struct DownloadFlags: u32 {
+        const NONE = 0b00000000;
+
+        /// Overwrite file if it already exists.
+        const FORCE = 0b00000001;
+
+        /// Open file after downloading.
+        const OPEN = 0b00000010;
+    }
+}
+
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub enum RoomField {
     Name,
diff --git a/src/commands.rs b/src/commands.rs
index f0373cc..363dd88 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -10,6 +10,7 @@ use modalkit::{
 };
 
 use crate::base::{
+    DownloadFlags,
     IambAction,
     IambId,
     MessageAction,
@@ -317,7 +318,29 @@ fn iamb_download(desc: CommandDescription, ctx: &mut ProgContext) -> ProgResult
         return Result::Err(CommandError::InvalidArgument);
     }
 
-    let mact = MessageAction::Download(args.pop(), desc.bang);
+    let mut flags = DownloadFlags::NONE;
+    if desc.bang {
+        flags |= DownloadFlags::FORCE;
+    };
+    let mact = MessageAction::Download(args.pop(), flags);
+    let iact = IambAction::from(mact);
+    let step = CommandStep::Continue(iact.into(), ctx.context.take());
+
+    return Ok(step);
+}
+
+fn iamb_open(desc: CommandDescription, ctx: &mut ProgContext) -> ProgResult {
+    let mut args = desc.arg.strings()?;
+
+    if args.len() > 1 {
+        return Result::Err(CommandError::InvalidArgument);
+    }
+
+    let mut flags = DownloadFlags::OPEN;
+    if desc.bang {
+        flags |= DownloadFlags::FORCE;
+    };
+    let mact = MessageAction::Download(args.pop(), flags);
     let iact = IambAction::from(mact);
     let step = CommandStep::Continue(iact.into(), ctx.context.take());
 
@@ -328,6 +351,7 @@ fn add_iamb_commands(cmds: &mut ProgramCommands) {
     cmds.add_command(ProgramCommand { names: vec!["cancel".into()], f: iamb_cancel });
     cmds.add_command(ProgramCommand { names: vec!["dms".into()], f: iamb_dms });
     cmds.add_command(ProgramCommand { names: vec!["download".into()], f: iamb_download });
+    cmds.add_command(ProgramCommand { names: vec!["open".into()], f: iamb_open });
     cmds.add_command(ProgramCommand { names: vec!["edit".into()], f: iamb_edit });
     cmds.add_command(ProgramCommand { names: vec!["invite".into()], f: iamb_invite });
     cmds.add_command(ProgramCommand { names: vec!["join".into()], f: iamb_join });
diff --git a/src/windows/room/chat.rs b/src/windows/room/chat.rs
index 680b669..8e41a01 100644
--- a/src/windows/room/chat.rs
+++ b/src/windows/room/chat.rs
@@ -4,6 +4,8 @@ use std::fs;
 use std::ops::Deref;
 use std::path::{Path, PathBuf};
 
+use tokio;
+
 use matrix_sdk::{
     attachment::AttachmentConfig,
     media::{MediaFormat, MediaRequest},
@@ -55,6 +57,7 @@ use modalkit::editing::{
 };
 
 use crate::base::{
+    DownloadFlags,
     IambAction,
     IambBufferId,
     IambError,
@@ -155,7 +158,7 @@ impl ChatState {
 
                 Ok(None)
             },
-            MessageAction::Download(filename, force) => {
+            MessageAction::Download(filename, flags) => {
                 if let MessageEvent::Original(ev) = &msg.event {
                     let media = client.media();
 
@@ -202,29 +205,42 @@ impl ChatState {
                         },
                     };
 
-                    if !force && filename.exists() {
-                        let msg = format!(
-                            "The file {} already exists; use :download! to overwrite it.",
-                            filename.display()
-                        );
-                        let err = UIError::Failure(msg);
+                    if filename.exists() {
+                        if !flags.contains(DownloadFlags::FORCE) {
+                            let msg = format!(
+                                "The file {} already exists; add ! to end of command to overwrite it.",
+                                filename.display()
+                            );
+                            let err = UIError::Failure(msg);
 
-                        return Err(err);
+                            return Err(err);
+                        }
+
+                        let req = MediaRequest { source, format: MediaFormat::File };
+
+                        let bytes =
+                            media.get_media_content(&req, true).await.map_err(IambError::from)?;
+
+                        fs::write(filename.as_path(), bytes.as_slice())?;
+
+                        msg.downloaded = true;
                     }
 
-                    let req = MediaRequest { source, format: MediaFormat::File };
+                    let info = if flags.contains(DownloadFlags::OPEN) {
+                        // open::that may not return until the spawned program closes.
+                        let target = filename.clone().into_os_string();
+                        tokio::task::spawn_blocking(move || open::that(target));
 
-                    let bytes =
-                        media.get_media_content(&req, true).await.map_err(IambError::from)?;
-
-                    fs::write(filename.as_path(), bytes.as_slice())?;
-
-                    msg.downloaded = true;
-
-                    let info = InfoMessage::from(format!(
-                        "Attachment downloaded to {}",
-                        filename.display()
-                    ));
+                        InfoMessage::from(format!(
+                            "Attachment downloaded to {} and opened",
+                            filename.display()
+                        ))
+                    } else {
+                        InfoMessage::from(format!(
+                            "Attachment downloaded to {}",
+                            filename.display()
+                        ))
+                    };
 
                     return Ok(info.into());
                 }