diff --git a/source/eventcore/driver.d b/source/eventcore/driver.d
index 66481e8..7b4afc1 100644
--- a/source/eventcore/driver.d
+++ b/source/eventcore/driver.d
@@ -426,6 +426,16 @@ interface EventDriverFiles {
 
 	ulong getSize(FileFD file);
 
+	/** Shrinks or extends a file to the specified size.
+
+		Params:
+			file = Handle of the file to resize
+			size = Desired file size in bytes
+			on_finish = Called when the operation finishes - the `size`
+				parameter is always set to zero
+	*/
+	void truncate(FileFD file, ulong size, FileIOCallback on_finish);
+
 	void write(FileFD file, ulong offset, const(ubyte)[] buffer, IOMode mode, FileIOCallback on_write_finish);
 	void read(FileFD file, ulong offset, ubyte[] buffer, IOMode mode, FileIOCallback on_read_finish);
 	void cancelWrite(FileFD file);
diff --git a/source/eventcore/drivers/threadedfile.d b/source/eventcore/drivers/threadedfile.d
index 13dbe1a..4a0a646 100644
--- a/source/eventcore/drivers/threadedfile.d
+++ b/source/eventcore/drivers/threadedfile.d
@@ -196,6 +196,22 @@ final class ThreadedFileEventDriver(Events : EventDriverEvents) : EventDriverFil
 		}
 	}
 
+	override void truncate(FileFD file, ulong size, FileIOCallback on_finish)
+	{
+		version (Posix) {
+			// FIXME: do this in the thread pool
+
+			if (ftruncate(cast(int)file, size) != 0) {
+				on_finish(file, IOStatus.error, 0);
+				return;
+			}
+			on_finish(file, IOStatus.ok, 0);
+		} else {
+			on_finish(file, IOStatus.error, 0);
+		}
+	}
+
+
 	final override void write(FileFD file, ulong offset, const(ubyte)[] buffer, IOMode, FileIOCallback on_write_finish)
 	{
 		//assert(this.writable);
diff --git a/source/eventcore/drivers/winapi/files.d b/source/eventcore/drivers/winapi/files.d
index 32bae89..0001073 100644
--- a/source/eventcore/drivers/winapi/files.d
+++ b/source/eventcore/drivers/winapi/files.d
@@ -88,6 +88,26 @@ final class WinAPIEventDriverFiles : EventDriverFiles {
 		return size.QuadPart;
 	}
 
+	override void truncate(FileFD file, ulong size, FileIOCallback on_finish)
+	@trusted {
+		auto h = idToHandle(file);
+
+		// FIXME: do this in a separate thread
+
+		LARGE_INTEGER li = {QuadPart: size};
+		if (!SetFilePointerEx(h, li, null, FILE_BEGIN)) {
+			on_finish(file, IOStatus.error, 0);
+			return;
+		}
+
+		if (!SetEndOfFile(h)) {
+			on_finish(file, IOStatus.error, 0);
+			return;
+		}
+
+		on_finish(file, IOStatus.ok, 0);
+	}
+
 	override void write(FileFD file, ulong offset, const(ubyte)[] buffer, IOMode mode, FileIOCallback on_write_finish)
 	{
 		auto h = idToHandle(file);