Kim and newborn daughter North stayed home while the rest of the Kardashian clan celebrated the birthday of the youngest child of Kris Jenner and Bruce Jenner.
Kylie was on the receiving end of several online birthday messages from family and friends that included adorable intimate portraits.
Sweet sixteen: Kim Kardashian wished her little sister Kylie Jenner a happy birthday on Saturday and shared photos of her younger sibling and her sister Kendall
Kim wasn't the only no-show at Kylie's birthday dinner. Kim's other half and North's father, Kanye West, didn't make it to the family outing and Khloe Kardashian's husband Lamar Odom also was not in attendance, according to a report in RadarOnline.com.
Kim did take time from new mommy duty to post a split photo showing Kylie with her older sister Kendall, 17, as young girls smiled cheek-to-cheek with a more recent shot of the teens similarly posing close together.
'Happy Birthday to my baby sis @kyliejenner !!!! Can't believe your 16! I love you so much!' Kim tweeted to her more than 18 million followers.
Getting it started: Khloe Kardashian posted a birthday message on Friday to her little sister
Kim also posted a six-picture photo montage showing Kylie with various members of the Kardashian clan.
Khloe Kardashian, 29, jumped the gun and posted a happy birthday message on Friday showing her and little sister Kylie posing together with pouty lips.
She followed it up by posting six pictures of just her and Kylie together.
Six pack: Kim also shared a six-photo spread with her more than 18 million followers on Twitter
Sweet sisters: Kendall Jenner shared nine photos of her and little sister Kylie
'Happy birthday to my sweet sweet @kyliejenner. No one could ever understand the bond we have and I love that! We understand our weirdness and that's love man!' Khloe wrote in the caption.
Kourtney Kardashian, 34, took it up a notch and posted a 30-photo montage of Kylie and the Kardashians.
'Happy Birthday @kyliejenner !!! Sixteen years old is a little crazy!,' Kourtney wrote in the caption. Kourtney also posted a photo of Kylie about to blow out her 16 candles.
Another six pack: Khloe posted six pictures of just her and Kylie and wrote about their strong bond
Kris Jenner also wished her daughter happy birthday online and shared a photo of them showing their striking resemblance.
Kylie's sister Kendall, 17, posted a nine-photo montage of images of the two sisters growing up together.
'happy birthday to my crazy, beautiful, wild little sister @kyliejenner !! can't believe you're turning 16! I love you and don't know what I would do without you! have an amazing day! lets party!,' her caption read.
Thirty pictures! Kourtney Kardashian trumped her sisters by sharing 30 photos for Kylie's birthday
Striking resemblance: Kris Jenner shared a photo of 'my beautiful Angel girl Kylie Jenner' who looks just like her
Good friend: Haily Baldwin wished her pal Kylie happy birthday and shared four photos of them having fun together
Make a wish: Kylie got her picture taken while preparing to blow out her candles
They were shown as little girls in matching dresses, posing on a tennis court together and wearing matching skirts.Kylie's friend Hailey Baldwin, 17, also shared four photos showing the girls having a good time together.
'Happy 16th birthday to my wifey @kyliejenner I am grateful to have such a great friend and I hope you have the best day today. Love you [heart symbol],' her caption read.
Famous family: Kylie has leveraged her exposure on Keeping Up With The Kardashians to gain her won collection of clothes along with older sister Kendall
Pop culture princess: Kim Kardashian, shown in April in New York City, shared photos of little sister Kylie on her 16th birthday
Next generation: Hailey Baldwin, shown in May in New York City, and good friend Kylie were seen having fun together in the online birthday photos