diff --git a/README.md b/README.md
index e9e3043..d381456 100644
--- a/README.md
+++ b/README.md
@@ -55,7 +55,7 @@ river -c /path/to/config.sh
 An example script with sane defaults is provided [here](contrib/config.sh) in
 the contrib directory.
 
-Some configuration options are still hardcoded in [Config.zig](src/Config.zig).
+Some configuration options are still hardcoded in [Config.zig](river/Config.zig).
 Eventually all configuration will be moved to the `riverctl` binary.
 
 ## Development
diff --git a/doc/riverctl.1 b/doc/riverctl.1
index df59ffb..1b93f9f 100644
--- a/doc/riverctl.1
+++ b/doc/riverctl.1
@@ -159,6 +159,19 @@ can be any of the above commands.
 A mapping without modifiers can be created by passing an empty string as the
 modifiers argument.
 
+.TP
+.B set-option \c
+.I option value
+Set
+.I option
+to a specified
+.IR value .
+List of valid options:
+.IP 	\(bu
+border_width (non-negative integer)
+.IP 	\(bu
+outer_padding (non-negative integer)
+
 .SH EXAMPLES
 
 Bind bemenu-run to Super+P:
diff --git a/river/Control.zig b/river/Control.zig
index 89b009f..96d587f 100644
--- a/river/Control.zig
+++ b/river/Control.zig
@@ -120,6 +120,7 @@ fn runCommand(
                 switch (err) {
                     command.Error.NoCommand => "no command given",
                     command.Error.UnknownCommand => "unknown command",
+                    command.Error.UnknownOption => "unknown option",
                     command.Error.NotEnoughArguments => "not enough arguments",
                     command.Error.TooManyArguments => "too many arguments",
                     command.Error.Overflow => "value out of bounds",
diff --git a/river/command.zig b/river/command.zig
index 243acfa..9f045fe 100644
--- a/river/command.zig
+++ b/river/command.zig
@@ -32,6 +32,7 @@ const impl = struct {
     const modMasterFactor = @import("command/mod_master_factor.zig").modMasterFactor;
     const sendToOutput = @import("command/send_to_output.zig").sendToOutput;
     const setFocusedTags = @import("command/tags.zig").setFocusedTags;
+    const setOption = @import("command/set_option.zig").setOption;
     const setViewTags = @import("command/tags.zig").setViewTags;
     const spawn = @import("command/spawn.zig").spawn;
     const toggleFloat = @import("command/toggle_float.zig").toggleFloat;
@@ -54,6 +55,20 @@ pub const Direction = enum {
     }
 };
 
+pub const Option = enum {
+    BorderWidth,
+    OuterPadding,
+
+    pub fn parse(str: []const u8) error{UnknownOption}!Option {
+        return if (std.mem.eql(u8, str, "border_width"))
+            Option.BorderWidth
+        else if (std.mem.eql(u8, str, "outer_padding"))
+            Option.OuterPadding
+        else
+            error.UnknownOption;
+    }
+};
+
 // TODO: this could be replaced with a comptime hashmap
 // zig fmt: off
 const str_to_impl_fn = [_]struct {
@@ -72,6 +87,7 @@ const str_to_impl_fn = [_]struct {
     .{ .name = "mod-master-factor",   .impl = impl.modMasterFactor },
     .{ .name = "send-to-output",      .impl = impl.sendToOutput },
     .{ .name = "set-focused-tags",    .impl = impl.setFocusedTags },
+    .{ .name = "set-option",          .impl = impl.setOption },
     .{ .name = "set-view-tags",       .impl = impl.setViewTags },
     .{ .name = "spawn",               .impl = impl.spawn },
     .{ .name = "toggle-float",        .impl = impl.toggleFloat },
@@ -89,6 +105,7 @@ pub const Error = error{
     Overflow,
     InvalidCharacter,
     InvalidDirection,
+    UnknownOption,
     OutOfMemory,
     CommandFailed,
 };
diff --git a/river/command/set_option.zig b/river/command/set_option.zig
new file mode 100644
index 0000000..303ae83
--- /dev/null
+++ b/river/command/set_option.zig
@@ -0,0 +1,46 @@
+// This file is part of river, a dynamic tiling wayland compositor.
+//
+// Copyright 2020 Rishabh Das
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const Error = @import("../command.zig").Error;
+const Option = @import("../command.zig").Option;
+const Seat = @import("../Seat.zig");
+
+/// Set option to a specified value.
+pub fn setOption(
+    allocator: *std.mem.Allocator,
+    seat: *Seat,
+    args: []const []const u8,
+    failure_message: *[]const u8,
+) Error!void {
+    if (args.len < 3) return Error.NotEnoughArguments;
+    if (args.len > 3) return Error.TooManyArguments;
+
+    // Parse option and value.
+    const option = try Option.parse(args[1]);
+    const value = try std.fmt.parseInt(u32, args[2], 10);
+
+    // Assign value to option.
+    switch (option) {
+        .BorderWidth => seat.focused_output.root.server.config.border_width = value,
+        .OuterPadding => seat.focused_output.root.server.config.outer_padding = value,
+    }
+
+    // 'Refresh' focused output to display the desired changes.
+    seat.focused_output.root.arrange();
+}