Katerina Cilka (Bulgarian: Катерина Цилка; 1868 – 22 June 1952) was a Bulgarian Protestant missionary from Bansko, abducted for ransom by a detachment of the pro-Bulgarian Inner Macedonian Revolutionary Organization (IMRO) in 1901 and released in 1902.

Cilka was a sister of the Sofia University Professor Constantine Stephanove.

[3] She moved to the United States to study at the Northfield Seminary and the Charity Nursing School of the Presbyterian Hospital (New York City).

In the summer of 1901, Cilka helped Ellen Stone, who had to take a short training course for Bulgarian teachers in primary Protestant schools in her native Bansko.

On 3 September 1901, Yane Sandanski and Hristo Chernopeev's chetas abducted both Stone and Cilka.