diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e3c4077..0155d9e9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 * Clarify where and how dotted keys define tables.
 * Add new `\e` shorthand for the escape character.
 * Add \x00 notation to basic strings.
+* Seconds in Date-Time and Time values are now optional.
 
 ## 1.0.0 / 2021-01-11
 
diff --git a/toml.abnf b/toml.abnf
index 3d926ee7..a902c19b 100644
--- a/toml.abnf
+++ b/toml.abnf
@@ -176,7 +176,7 @@ time-secfrac   = "." 1*DIGIT
 time-numoffset = ( "+" / "-" ) time-hour ":" time-minute
 time-offset    = "Z" / time-numoffset
 
-partial-time   = time-hour ":" time-minute ":" time-second [ time-secfrac ]
+partial-time   = time-hour ":" time-minute [ ":" time-second [ time-secfrac ] ]
 full-date      = date-fullyear "-" date-month "-" date-mday
 full-time      = partial-time time-offset
 
diff --git a/toml.md b/toml.md
index 58232cd9..57f8c653 100644
--- a/toml.md
+++ b/toml.md
@@ -554,6 +554,14 @@ time with a space character (as permitted by RFC 3339 section 5.6).
 odt4 = 1979-05-27 07:32:00Z
 ```
 
+One exception to RFC 3339 is permitted: seconds may be omitted, in which case
+`:00` will be assumed. The offset immediately follows the minutes.
+
+```toml
+odt5 = 1979-05-27 07:32Z
+odt6 = 1979-05-27 07:32-07:00
+```
+
 Millisecond precision is required. Further precision of fractional seconds is
 implementation-specific. If the value contains greater precision than the
 implementation can support, the additional precision must be truncated, not
@@ -573,6 +581,12 @@ ldt1 = 1979-05-27T07:32:00
 ldt2 = 1979-05-27T00:32:00.999999
 ```
 
+Seconds may be omitted, in which case `:00` will be assumed.
+
+```toml
+ldt3 = 1979-05-27T07:32
+```
+
 Millisecond precision is required. Further precision of fractional seconds is
 implementation-specific. If the value contains greater precision than the
 implementation can support, the additional precision must be truncated, not
@@ -602,6 +616,12 @@ lt1 = 07:32:00
 lt2 = 00:32:00.999999
 ```
 
+Seconds may be omitted, in which case `:00` will be assumed.
+
+```toml
+lt3 = 07:32
+```
+
 Millisecond precision is required. Further precision of fractional seconds is
 implementation-specific. If the value contains greater precision than the
 implementation can support, the additional precision must be truncated, not