The interests he failed to register included payments for Black History Month speaking engagements and appearances on a commercial radio station.
There were also tickets to American football and boxing matches in London.
Under the rules, MPs must register changes to their financial interests within 28 days.
In her summary, Parliamentary Standards Commissioner Kathryn Stone said she initially opened an inquiry on June 16.
It came after she received an allegation that Mr Lammy was involved in eight events between October 7 and November 15, 2021, which he failed to register within the set timeframe.
Ms Stone then undertook a review of Mr Lammy’s register entry and found a further seven interests that had been registered late.
The Shadow Foreign Secretary went on to bring to Ms Stone’s attention another “single late declaration”, which was added to the scope of the investigation.
The commissioner said she was satisfied “there was no deliberate intention to mislead”.
But she concluded that Mr Lammy did breach the code by registering a total of 16 interests outside the 28-day deadline.
This was “as a result of inattention to detail”, she said, and found the breaches were “inadvertent”.
She concluded that a referral to the Standards Committee was “not necessary”.
Mr Lammy failed to register payments for Black History Month speaking engagements
Aaron Chown
Mr Lammy is currently Shadow Foreign Secretary
PETER CZIBORRA