diff --git a/proposals/README.md b/proposals/README.md
index 73eb38f942cc..81fa60d4205e 100644
--- a/proposals/README.md
+++ b/proposals/README.md
@@ -64,5 +64,6 @@ request:
 -   [0199 - String literals](p0199.md)
     -   [0199 - Decision](p0199_decision.md)
 -   [0253 - 2021 Roadmap](p0253.md)
+    -   [0253 - Decision](p0253_decision.md)
 
 <!-- endproposals -->
diff --git a/proposals/p0253_decision.md b/proposals/p0253_decision.md
new file mode 100644
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@@ -0,0 +1,48 @@
+# Decision for: Proposed Carbon roadmap for 2021
+
+<!--
+Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+Exceptions. See /LICENSE for license information.
+SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+-->
+
+Proposal accepted on 2021-03-09
+
+Affirming:
+
+-   [austern](https://github.com/austern)
+-   [chandlerc](https://github.com/chandlerc)
+-   [geoffromer](https://github.com/geoffromer)
+-   [gribozavr](https://github.com/gribozavr)
+-   [josh11b](https://github.com/josh11b)
+-   [noncombatant](https://github.com/noncombatant)
+-   [zygoloid](https://github.com/zygoloid)
+
+Abstaining:
+
+-   [tituswinters](https://github.com/tituswinters)
+
+## Rationale
+
+By its nature, we're not sure a planning document like this can directly advance
+Carbon's goals, but we think this roadmap does a good job of keeping us focused
+on the work that will help us generate concrete evidence as to whether Carbon is
+likely to successfully achieve those goals (and help us figure out how to
+course-correct if it's not). Increasing the representation of non-Googlers on
+the core team is an important indicator (as well as enabler) of building an
+"open and inclusive community", not to mention of having a broad enough user
+base to succeed, and the example ports, demo implementation, and executable
+semantics will help us concretely evaluate how well Carbon is meeting all of its
+language goals.
+
+In addition, as the proposal argues, concrete evidence that Carbon can succeed
+will indirectly help Carbon make faster progress, by motivating further
+investment in the project. Some aspects of the roadmap will also help accelerate
+Carbon's development in more direct ways. In particular, the executable
+semantics implementation should enable Carbon contributors to rapidly prototype
+potential new features, which will help us identify and solve more problems at
+an earlier stage, and have higher confidence in the proposals we adopt.
+
+While rapid progress is not an explicit goal of the Carbon project, Carbon can't
+meet any of its other goals until it exists in a usable form, and the longer it
+takes to reach that point, the less likely it is to reach it at all.